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ΑΡΙΘΜΟΙ 2001 - 3000

2001 has a square with the first 3 digits the same as the next 3 digits.

2002 = ₁₄C₅.

2003 is a Lucas 8-step number.

2004 has a square with the last 3 digits the same as the 3 digits before that.

2007 divides the sum of the digits of 2²⁰⁰⁷ × 2007!.

2008 is a Kaprekar constant in base 3.

2009 ! ends in exactly 500 zeros.

2010 is the number of trees on 15 vertices with diameter 7.

2015 is a Lucas-Carmichael number.

2016 is a value of n for which n² + n³ contains one of each digit.

2017 is a value of n for which φ(n) = φ(n-1) + φ(n-2).

2020 is an autobiographical number.

2021 is the product of two consecutive primes.

2024 = ₂₄C₃.

2025 is a square that remains square if all its digits are incremented.

2028 is the number of graphs with 9 vertices that have chromatic number 6.

2029 is an Eisenstein-Mersenne prime.

2030 is the smallest number that can be written as a sum of 3 or 4 consecutive squares.

2034 is the number of self-avoiding walks of length 9.

2036 is the number of ways 11 people can line up so that only one person has a taller person in front of him.

2037 is a truncated cube number.

2038 is the number of Eulerian graphs with 9 vertices.

2039 is the smallest prime that contains ten 1's in binary.

2040 = 2040₅ + 2040₇ + 2040₈.

2041 is a 12-hyperperfect number.

2044 is the number of rectangles with corners on an 9×9 grid of points.

2045 is the number of unlabeled partially ordered sets of 7 elements.

2046 is the maximum number of pieces a torus can be cut into with 22 cuts.

2047 is the smallest composite Mersenne number with prime exponent.

2048 is the smallest non-trivial 11^th power.

2049 is a Cullen number.

2050 is the number of subsets of the 22^nd roots of unity that add to 0.

2052 is the magic constant for a 8×8×8 magic cube.

2053 is a value of n for which one less than the product of the first n primes is prime.

2054 is the number of subsets of the 33^rd roots of unity that add to 0.

2055 is the rectilinear crossing number of complete graph K₂₁

2056 is the magic constant of a 16×16 magic square.

2057 is a centered icosahedral number.

2058 is the number of integers with complexity 27.

2059 is a centered tetrahedral number.

2061 is the number of sets of distinct positive integers with mean 7.

2063 is a member of the Fibonacci-type sequence starting with 3 and 7.

2067 is a value of n so that n(n+5) is a palindrome.

2072 is the smallest number that can be written in exactly 6 ways as the sum of a number and the product of its non-zero digits.

2073 is a Genocchi number.

2074 is the smallest number that can not be formed using the digit 1 at most 24 times, together with the symbols +, –, × and ÷.

2075 is the number of connected graphs with 9 vertices and 11 edges.

2076 is a value of n for which n!!! + 1 is prime.

2078 has a cube whose digits occur with the same frequency.

2080 is the number of different arrangements (up to rotation and reflection) of 26 non-attacking bishops on a 14×14 chessboard.

2081 is a number n for which n, n+2, n+6, and n+8 are all prime.

2082 is the sum of its proper divisors that contain the digit 4.

2086 is a number n for which φ(n) is a repdigit.

2089 is the smallest number that ends an arithmetic progression of 10 numbers with the same prime signature.

2090 is the number of possible rows in a 17×17 crossword puzzle.

2100 is divisible by its reverse.

2101 = 2101₅ + 2101₇ + 2101₈.

2108 does not occur in its factorial in base 2.

2109 is a value of n so that n(n+7) is a palindrome.

2110 is a value of n for which reverse(φ(n)) = φ(reverse(n)).

2112 is the number of subsets of {1, 1/2, 1/3, ... 1/36} that sum to an integer.

2113 is a Proth prime.

2114 is a number whose product of digits is equal to its sum of digits.

2116 has a base 10 representation which is the reverse of its base 7 representation.

2118 is a member of the Fibonacci-type sequence starting with 1 and 5.

2119 is a value of n for which |cos(n)| is smaller than any previous integer.

2120 is the number of ways to stack 16 pennies in a line so that each penny lies on the table or on two pennies.

2122 is the index of a prime Euclid number.

2126 is a value of n so that n(n+3) is a palindrome.

2127 is not the sum of a square, a cube, a 4^th power, and a 5^th power.

2128 is the 7^th central quadrinomial coefficient.

2130 and its reverse are both the averages of twin primes.

2131 is the number of domino tilings of a 3×12 rectangle.

2132 is the maximum number of 11^th powers needed to sum to any number.

2133 is a 2-hyperperfect number.

2135 is a value of n for which σ(n-1) + σ(n+1) = σ(2n).

2136 is the number of different degree sequences possible for a graph with 15 edges.

2137 does not occur in its factorial in base 2.

2138 does not occur in its factorial in base 2.

2140 is a cubic star number.

2141 is a number whose product of digits is equal to its sum of digits.

2143 is the number of commutative semigroups of order 6.

2146 is a value of n for which 2φ(n) = φ(n+1).

2147 has a square with the last 3 digits the same as the 3 digits before that.

2148 is the number of 15-ominoes with a horizontal or vertical line of symmetry.

2150 divides the sum of the largest prime factors of the first 2150 positive integers.

2155 is the smallest number whose cube has 10 digits.

2156 is the number of different positions in Connect Four after 5 moves.

2158 is a number n for which n²+1 is 6 times another square.

2160 is the order of a perfect group.

2161 is a prime factor of 111111111111111111111111111111.

2163 are the first 4 digits of π²¹⁶³.

2164 is the smallest number whose 7^th power starts with 5 identical digits.

2167 is the number of partitions of 34 that do not contain 1 as a part.

2168 is a structured hexagonal diamond number.

2169 is a Leyland number.

2176 is the number of prime knots with 12 crossings.

2178 is the only number known which when multiplied by its reverse yields a 4^th power.

2179 is a Wedderburn-Etherington number.

2182 is the number of degree 15 irreducible polynomials over GF(2).

2184 is the product of three consecutive Fibonacci numbers.

2185 is the number of digits of 5⁵⁵.

2186 = 2222222 in base 3.

2187 is a strong Friedman number.

2188 is the 10^th Motzkin number.

2192 is the number of necklaces (that can't be turned over) possible with 15 beads, each being one of 2 colors.

2194 is the number of partitions of 42 in which no part occurs only once.

2195 is the number of necklaces with 9 beads, each one of 3 colors.

2196 is the only number n so that 2n, 3n, 7n, and 9n together contain every digit 1-9 exactly twice.

2197 = 13³.

2199 is a perfect totient number.

2201 is the only non-palindrome known to have a palindromic cube.

2202 is a factor of the sum of the digits of 2202²²⁰².

2203 is the exponent of a Mersenne prime.

2204 has the property that the sum of the factorials of its digits is its largest prime factor.

2205 is an odd primitive abundant number.

2207 is the 16^th Lucas number.

2208 is a Keith number.

2209 is a Tribonacci-like number starting from 1, 1, and 1.

2210 = ₄₇C₂ + ₄₇C₂ + ₄₇C₁ + ₄₇C₀.

2211 is a triangular number whose internal digits are triangular and whose external digits are triangular.

2212 is the closest integer to 17^e.

2213 = 2³ + 2³ + 13³.

2217 has a base 2 representation that begins with its base 3 representation.

2219 is the number of 14-hexes with reflectional symmetry.

2221 is a value of n for which σ(n) is a repdigit.

2222 is the smallest number divisible by a 1-digit prime, a 2-digit prime, and a 3-digit prime.

2223 is a Kaprekar number.

2225 has the property that the sum of the n^th powers of its digits is prime for 1 ≤ n &\le 9.

2226 is the smallest number whose cube contains 4 consecutive 9's.

2228 is the number of congruency classes of triangles with vertices from a 11×11 grid of points.

2230 is a number n for which φ(n) is a repdigit.

2234 is the number of ways to stack 24 pennies in contiguous rows so that each penny lies on the table or on two pennies.

2235 is a value of n so that n(n+8) is a palindrome.

2239 is a prime that remains prime if any digit is deleted.

2240 is the number of unsymmetrical ways to dissect a regular 13-gon into 11 triangles.

2241 is the sum of 3 consecutive cubes.

2243 is the smallest prime so that it and the next 2 primes are all equal to 3 (mod 8).

2244 is the generalized Catalan number C(14,4).

2245 is the number of ways to tile a 8×4 rectangle with 2×1 rectangles.

2250 is the number of necklaces possible with 16 beads, each being one of 2 colors.

2252 is a Franel number.

2253 is the number of monic polynomials of degree 11 with integer coefficients whose complex roots are all in the unit disk.

2255 is the number of triangles of any size contained in the triangle of side 20 on a triangular grid.

2257 = 4321 in base 8.

2258 is the number of anisohedral 16-ominoes.

2260 is an icosahedral number.

2261 = 2222 + 22 + 6 + 11.

2263 = 2222 + 2 + 6 + 33.

2264 is the number of graphs with 8 vertices that have 4 automorphisms.

2266 is a dodecagonal pyramidal number.

2268 is the number of binary partitions of 34.

2269 is a Cuban prime.

2272 is the number of graphs on 7 vertices with no isolated vertices.

2273 is the number of functional graphs on 10 vertices.

2274 is the sum of its proper divisors that contain the digit 7.

2275 is the sum of the first six 4^th powers.

2277 is the trinomial coefficient T(11,6).

2281 is the exponent of a Mersenne prime.

2282 is the number of ways, up to rotation and reflection, of dissecting a regular 13-gon into 11 triangles.

2284 is the number of 7-digit perfect powers.

2285 is a non-palindrome with a palindromic square.

2291 is the number of inequivalent Ferrers graphs with 29 points.

2292 is a narcissistic number in base 6.

2293 is a prime that remains prime if any digit is deleted.

2295 is the smallest number so that it and its successor are both the product of 2 primes and the cube of a prime.

2296 is a structured great rhombicubeoctahedral number.

2297 is the number of inequivalent binary linear codes of length 10.

2299 is the number of ordered sequences of coins totaling 28 cents.

2300 = ₂₅C₃.

2303 is a number whose square and cube use different digits.

2304 is the number of edges in a 9 dimensional hypercube.

2305 has a base 6 representation that ends with its base 8 representation.

2306 has a base 6 representation that ends with its base 8 representation.

2307 has a base 6 representation that ends with its base 8 representation.

2308 is the number of conjugacy classes of the alternating group A₂₉.

2309 is the largest prime factor of 2 × 3 × 5 × 7 × 11 - 1.

2310 is the product of the first 5 primes.

2311 is a Euclid number.

2312 is the number of series-reduced planted trees with 10 leaves.

2316 = 1⁷ + 2⁷ + 3⁷.

2318 is the number of connected planar graphs with 10 edges.

2320 is the maximum number of regions space can be divided into by 20 spheres.

2321 is a Huay rhombic dodecahedral number.

2322 is the number of connected graphs with 10 edges.

2323 is the maximum number of pieces a torus can be cut into with 23 cuts.

2324 is a narcissistic number in base 6.

2325 is the maximum number of regions a cube can be cut into with 24 cuts.

2326 is the smallest number whose cube contains every digit at least once.

2328 is the number of groups of order 128.

2331 is a centered cube number.

2333 is a right-truncatable prime.

2336 is the number of sided 11-iamonds.

2339 is the number of ways to tile a 6×10 rectangle with the pentominoes.

2340 = 4444 in base 8.

2342 is the number of subsets of {1,2,3,...,15} that have a sum divisible by 14.

2343 = 33333 in base 5.

2344 is the number of necklaces with 7 beads, each one of 4 colors.

2345 has digits in arithmetic sequence.

2349 is a Friedman number.

2350 is the number of quasi-triominoes that fit inside a 11×11 grid.

2351 is a member of the Fibonacci-type sequence starting with 2 and 5.

2352 does not occur in its factorial in base 2.

2353 has the property that 588² + 2353² = 5882353 and 9412² + 2353² = 94122353.

2354 = 2222 + 33 + 55 + 44.

2357 is a SmarandacheΠWellin prime.

2359 = 2222 + 33 + 5 + 99.

2360 is a hexagonal pyramidal number.

2363 does not occur in its factorial in base 2.

2365 is a value of n for which n (n+2) is a palindrome.

2366 is the number of ways to legally add 2 sets of parentheses to a product of 12 variables.

2368 is the number of 3×3 sliding puzzle positions that require exactly 14 moves to solve starting with the hole in the center.

2371 is the number of ways a 7×1 rectangle can be surrounded by 7×1 rectangles.

2372 is the smallest number whose 8^th power has 27 digits.

2376 is a structured truncated tetrahedral number.

2377 is a value of n for which one less than the product of the first n primes is prime.

2378 is the 10^th Pell number.

2380 = ₁₇C₄.

2385 is the smallest number whose 7^th power contains exactly the same digits as another 7^th power.

2387 is a structured rhombic triacontahedral number.

2388 is the number of 3-connected graphs with 8 vertices.

2391 is the number of ways to flip a coin 12 times and get at least 3 heads in a row.

2393 is a right-truncatable prime.

2394 is the smallest value of n for which n and 7n together use each digit 1-9 exactly once.

2397 is the number of intersections when all the diagonals of a regular 17-gon are drawn.

2398 is the number of 3×3 sliding puzzle positions that require exactly 28 moves to solve starting with the hole in the center.

2399 is a right-truncatable prime.

2400 = 6666 in base 7.

2401 is the 4^th power of the sum of its digits.

2402 has a base 2 representation that begins with its base 7 representation.

2405 has the property that if each digit is replaced by its square, the resulting number is a square.

2406 is a truncated octahedral number.

2407 is a value of n for which σ(φ(n)) = 2σ(n).

2410 is the number of 3-valent trees with 16 vertices.

2411 is a number whose product of digits is equal to its sum of digits.

2414 is the number of symmetric plane partitions of 28.

2417 has a base 3 representation that begins with its base 7 representation.

2420 is the number of possible rook moves on a 11×11 chessboard.

2424 has a cube that contains the digits 2424 in reverse order.

2427 = 2¹ + 4² + 2³ + 7⁴.

2430 is the number of unordered ways to write 1 as a sum of reciprocals of integers no larger than 18.

2431 is the Stirling number of the second kind S(13,11).

2432 does not occur in its factorial in base 2.

2434 is the number of legal king moves in Chess.

2436 is the number of partitions of 26.

2445 is a truncated tetrahedral number.

2448 is the order of a non-cyclic simple group.

2450 has a base 3 representation that begins with its base 7 representation.

2457 = 169 + 170 + . . . + 182 = 183 + 184 + . . . + 195.

2460 = 3333 in base 9.

2464 is the number of permutations of 8 items that fix 3 elements.

2465 is a Carmichael number.

2466 is the number of regions formed when all diagonals are drawn in a regular 18-gon.

2467 has a square with the first 3 digits the same as the next 3 digits.

2468 = 2 + 22 + 222 + 2222.

2469 is the smallest value of n for which 4n and 5n together use the digits 1-9 exactly once.

2470 is the sum of the first 19 squares.

2471 is the smallest number that can not be formed using the numbers 2⁰, 2¹, ... , 2⁶, together with the symbols +, –, × and ÷.

2474 is a value of n for which |cos(n)| is smaller than any previous integer.

2477 would be prime if preceded and followed by a 1, 3, 7, or 9.

2478 is the number of anisohedral 20-iamonds.

2484 is the number of regions the complex plane is cut into by drawing lines between all pairs of 18^th roots of unity.

2485 is the number of planar partitions of 13.

2487 has a 4^th power that is the sum of four 4^th powers.

2491 is the product of two consecutive primes.

2492 is the larger number in a Ruth-Aaron pair.

2495 is the number of 13-iamonds that tile the plane.

2496 is the number of 3-connected planar maps with 17 edges.

2498 shares 3 consecutive digits with one of its prime factors.

2499 has a square root that starts 49.989998999....

2500 is a Tetranacci-like number starting from 1, 1, 1, and 1.

2501 is a Friedman number.

2502 is a strong Friedman number.

2503 is a Friedman number.

2504 is a Friedman number.

2505 is a Friedman number.

2506 is a Friedman number.

2507 is a Friedman number.

2508 is a Friedman number.

2509 is a Friedman number.

2510 is the maximum value of n so that there exist 6 denominations of stamps so that every postage from 1 to n can be paid for with at most 10 stamps.

2511 is the smallest number so that it and its successor are both the product of a prime and the 4^th power of a prime.

2512 is the smallest number whose 5^th power has 17 digits.

2513 is a Padovan number.

2515 is the number of symmetric 9-cubes.

2517 is the number of regions the complex plane is cut into by drawing lines between all pairs of 17^th roots of unity.

2518 uses the same digits as φ(2518).

2519 is the smallest number n where either n or n+1 is divisible by the numbers from 1 to 12.

2520 is the smallest number divisible by 1 through 10.

2522 is the number of subsets of {1,2,3,...,15} that have a sum divisible by 13.

2524 and the two numbers before it and after it are all products of exactly 3 primes.

2525 and the two numbers before it and after it are all products of exactly 3 primes.

2528 is a structured truncated octahedral number.

2530 is a Leyland number.

2532 = 2222 + 55 + 33 + 222.

2535 is the number of ways to 13-color the faces of a tetrahedron.

2538 has a square with 5/7 of the digits are the same.

2540 has a square root whose decimal part starts with the digits 0-9 in some order.

2542 is the number of stretched 9-ominoes.

2545 = 2545₆ + 2545₉.

2548 is the generalized Catalan number C(11,5).

2550 is a Kaprekar constant in base 4.

2557 is the number of proper divisors of the 15^th perfect number.

2558 is the number of divisors of the 15^th perfect number.

2560 is the number of 2×2 singular matrices mod 8.

2561 is the number of digits of the 19^th perfect number.

2562 is a structured pentakis dodecahedral number.

2570 is the number of subsets of {1,2,3,...,14} that have an integer average.

2571 is the smallest number with the property that its first 7 multiples contain the digit 1.

2573 is the number of partitions of 35 that do not contain 1 as a part.

2574 is a value of n for which _2nC_n is divisible by n².

2576 has exactly the same digits in 3 different bases.

2580 is a Keith number.

2581 is the smallest number whose square begins with three 6's.

2582 is the smallest number whose square begins with four 6's.

2583 is the sum of the first 16 Fibonacci numbers.

2584 is the 18^th Fibonacci number .

2585 is a truncated square pyramid number.

2587 is a value of n for which φ(n) + φ(n+1) divides σ(n) + σ(n+1).

2590 is the number of partitions of 47 into distinct parts.

2592 = 2⁵ 9².

2593 has a base 3 representation that ends with its base 6 representation.

2594 has a base 3 representation that ends with its base 6 representation.

2596 is the number of triangles of any size contained in the triangle of side 21 on a triangular grid.

2600 = ₂₆C₃.

2601 is a pentagonal pyramidal number.

2606 is the number of polyhedra with 9 vertices.

2609 is the number of perfect squared rectangles of order 15.

2614 is the smallest value of n for which π(9n) = n.

2615 is the number of functions from 9 unlabeled points to themselves.

2616 is the number of graphs with 9 vertices and 6 cycles.

2617 is the index of a Wagstaff prime.

2618 has a sum of digits equal to its largest prime factor.

2620 is an amicable number.

2621 = 2222 + 66 + 222 + 111.

2622 is a value of n for which 7n and 8n together use each digit exactly once.

2623 = 2222 + 66 + 2 + 333.

2624 is the maximum number of pieces a torus can be cut into with 24 cuts.

2625 is a centered octahedral number.

2626 is the maximum number of regions a cube can be cut into with 25 cuts.

2627 is a Perrin number.

2629 is the smallest number whose reciprocal has period 14.

2631 is a Lucas 4-step number.

2632 has the same digits as the 2632^nd prime.

2635 is the number of necklaces with 6 beads, each one of 5 colors.

2636 is a non-palindrome with a palindromic square.

2637 is the number of commutative monoids of order 7.

2639 is an enneagonal pyramidal number.

2641 is the pseudosquare modulo 11.

2642 = 5² + 6³ + 7⁴.

2646 is the Stirling number of the second kind S(9,6).

2647 is the index of a prime Euclid number.

2651 is the number of asymmetric trees with 12 vertices.

2652 is the 9^th super-ballot number.

2657 is a value of n for which one more than the product of the first n primes is prime.

2659 is the maximum value of n so that there exist 5 denominations of stamps so that every postage from 1 to n can be paid for with at most 13 stamps.

2662 is a palindrome and the 2662^nd triangular number is a palindrome.

2663 is the number of digits of the 20^th perfect number.

2664 is the smallest value of n for which n, n+1, n+2, n+3, and n+4 have the same number of prime factors.

2665 is the number of conjugacy classes in the automorphism group of the 14 dimensional hypercube. 

2667 is a number whose sum of divisors is a 6^th power.

2668 is the number of lines through exactly 2 points of a 11×11 grid of points.

2671 is a value of n for which 2n and 7n together use the digits 1-9 exactly once.

2672 and its successor are both divisible by 4^th powers.

2673 is the largest number known that does not have any digits in common with its 4^th power.

2676 is a number n for which φ(n) is a repdigit.

2678 is the number of connected graphs with 10 vertices and 11 edges.

2680 is the number of different arrangements of 11 non-attacking queens on an 11×11 chessboard.

2682 is a number n for which φ(n) is a repdigit.

2683 is the largest n so that Q(√n) has class number 5.

2685 is a value of n for which σ(n) = σ(n+1).

2688 is the order of a perfect group.

2689 is a Proth prime.

2690 is the number of terms in the 9^th derivative of f(f(f(f(f(x))))).

2692 is the sum of the squares of 4 consecutive primes.

2694 is the number of ways 22 people around a round table can shake hands in a non-crossing way, up to rotation.

2697 is the smallest value of n for which n and 5n together use each digit 1-9 exactly once.

2700 is the product of the first 5 triangular numbers.

2701 is the smallest number n which divides the average of the n^th prime and the primes surrounding it.

2702 is the maximum number of regions space can be divided into by 21 spheres.

2704 is the number of necklaces with 9 white and 9 black beads.

2710 is an hexagonal prism number.

2712 is the number of 12-ominoes that tile the plane by translation.

2717 is the number of 9-hexes that do not tile the plane.

2718 is the integer part of 1000e.

2722 has the property that if each digit is replaced by its square, the resulting number is a square.

2725 is the number of fixed octominoes.

2728 is a Kaprekar number.

2729 has a square with the first 3 digits the same as the next 3 digits.

2730 = ₁₅P₃.

2731 is a Wagstaff prime.

2733 is the number of possible positions in Checkers after 5 moves.

2736 is an octahedral number.

2737 is a strong Friedman number.

2743 is a centered dodecahedral number.

2744 is the smallest number that can be written as the sum of a cube and a 4^th power in more than one way.

2745 divides the sum of the primes less than it.

2748 is ABC in hexadecimal.

2749 is the smallest index of a Fibonacci number whose first 9 digits are the digits 1-9 rearranged.

2751 is the number of ordered partitions of 21 into distinct parts.

2752 is a structured snub cubic number.

2753 is the number of subsequences of {1,2,3,...13} in which every odd number has an even neighbor.

2757 is the number of possible configurations of pegs (up to symmetry) after 7 jumps in solitaire.

2758 has the property that placing the last digit first gives 1 more than triple it.

2766 in hexadecimal spells the word ACE.

2767 is the smallest number that can not be formed using the digit 1 at most 25 times, together with the symbols +, –, × and ÷.

2768 is 7-automorphic.

2769 is a value of n for which n and 5n together use each digit 1-9 exactly once.

2770 is the Entringer number E(8,1).

2773 is the smallest number that can not be written as the sum of 3 volumes of rectangular boxes with integer dimensions less than 12.

2777 + σ(2777) = 5555.

2780 = 1⁸ + 2⁷ + 3⁶ + 4⁵ + 5⁴ + 6³ + 7² + 8¹.

2782 is the maximum value of n so that there exist 4 denominations of stamps so that every postage from 1 to n can be paid for with at most 19 stamps.

2783 is the smallest number whose 9^th power has 31 digits.

2786 is the 9^th Pell-Lucas number.

2787 is a value of n for which the first n binary digits of π form a prime.

2790 is the number of binary partitions of 36.

2791 is a Cuban prime.

2792 is the smallest number that can not be written using 13 copies of 13 and the operations +, –, ×, and ÷.

2793 is the number of inequivalent asymmetric Ferrers graphs with 30 points.

2801 = 11111 in base 7.

2802 is the sum of its proper divisors that contain the digit 4.

2805 is the smallest order of a cyclotomic polynomial whose factorization contains 6 as a coefficient.

2806 is the number of semigroups of order 6 with 2 idempotents.

2808 = (9 × 10 × 11 × 12 × 13) / (9 + 10 + 11 + 12 + 13) .

2810 has the property that the concatenation of its prime factors in increasing order is a square.

2811 is the number of inequivalent Ferrers graphs with 30 points.

2812 is the number of 8-pents.

2817 is a member of the Fibonacci-type sequence starting with 1 and 4.

2821 is a Carmichael number.

2824 is the smallest number whose cube contains six 2's.

2828 is a value of n so that n(n+8) is a palindrome.

2829 has a 4^th power that is the sum of four 4^th powers.

2832 is the number of ways to place 2 non-attacking bishops on a 9×9 chessboard.

2834 is a composite number n that divides the (n+1)^st Fibonacci number.

2835 is a Rhonda number.

2842 is the smallest number with the property that its first 4 multiples contain the digit 8.

2844 is the sum of the first 15 numbers that have digit sum 15.

2846 is a value of n for which n!!!! + 1 is prime.

2847 is a house number.

2848 is the smallest number whose square contains 4 consecutive 1's.

2849 is the largest number n known whose base 11 representation is equal to φ(n).

2850 is the trinomial coefficient T(10,4).

2855 is the smallest number that can not be formed using the digit 1 at most 21 times, together with the symbols +, × and ^.

2856 = 17!!!!!.

2857 is the number of partitions of 44 in which no part occurs only once.

2858 has a square with the first 3 digits the same as the next 3 digits.

2863 has a 10^th root whose decimal part starts with the digits 1-9 in some order.

2867 has the property that the concatenation of its prime factors in increasing order is a square.

2868 has a 4^th power containing only 4 different digits.

2869 is a centered icosahedral number.

2870 is the sum of the first 20 squares.

2871 is a cubic star number.

2872 is the 15^th Tetranacci number.

2874 is the number of multigraphs with 5 vertices and 12 edges.

2876 is the number of 8-hepts.

2878 is the number of integers with complexity 28.

2879 is the smallest number with complexity 27.

2880 = 4! × 5!.

2881 has a base 3 representation that ends with its base 6 representation.

2882 has a base 3 representation that ends with its base 6 representation.

2888 is the first of five consecutive squareful numbers.

2889 is a number n for which n²+1 is 5 times another square.

2890 is the smallest number in base 9 whose square contains the same digits in the same proportion.

2893 is the number of planar 2-connected graphs with 8 vertices.

2895 is the smallest n for which 38n contains only 0's and 1's.

2897 is a Markov number.

2900 is the number of self-avoiding walks in a quadrant of length 10.

2907 is the trinomial coefficient T(9,1).

2910 is the number of partitions of 48 into distinct parts.

2911 is a value of n for which σ(n-1) = σ(n+1).

2913 is a value of n for which σ(n-1) + σ(n+1) = σ(2n).

2914 is a value of n for which σ(n-1) = σ(n+1).

2915 is a Lucas-Carmichael number.

2916 is a Friedman number.

2917 is the number of digits of the 21^st Mersenne prime.

2918 is the number of ways to break {1,2,3, . . . ,15} into sets with equal sums.

2919 = (2 + 9 + 1 + 9) × (29 + 91 + 19).

2920 is a heptagonal pyramidal number.

2922 is the sum of its proper divisors that contain the digit 4.

2924 is an amicable number.

2925 = ₂₇C₃.

2926 has a sum of digits equal to its largest prime factor.

2928 is the number of partitions of 45 in which no part occurs only once.

2931 is the number of trees on 16 vertices with diameter 6.

2933 is a value of n for which σ(φ(n)) = 2σ(n).

2937 is a value of n for which n and 5n together use each digit 1-9 exactly once.

2938 is the number of binary rooted trees with 17 vertices.

2939 is a right-truncatable prime.

2943 is the smallest value of n for which n and 6n together use each digit 1-9 exactly once.

2947 is the smallest number whose 5^th power starts with 4 identical digits.

2950 is the maximum number of pieces a torus can be cut into with 25 cuts.

2952 is the maximum number of regions a cube can be cut into with 26 cuts.

2953 is the smallest number whose cube contains six 7's.

2955 has a 5^th power whose digits all occur twice.

2958 is the number of multigraphs with 21 vertices and 4 edges.

2964 is a Smith brother.

2965 is a Smith brother.

2966 has the property that if each digit is replaced by its square, the resulting number is a square.

2967 is a value of n for which 5n and 7n together use each digit exactly once.

2970 is a harmonic divisor number.

2971 is the index of a prime Fibonacci number.

2973 is a value of n for which n and 5n together use each digit 1-9 exactly once.

2974 is a value of n for which σ(n) = σ(n+1).

2978 is the number of unlabeled distributive lattices with 17 elements.

2981 is the closest integer to e⁸.

2982 is a value of n so that n(n+7) is a palindrome.

2983 is the number of trees on 28 vertices with diameter 4.

2984 is the number of different products of subsets of the set {1, 2, 3, ... 15}.

2988 is the number of series-reduced trees with 20 vertices.

2989 in hexadecimal spells the word BAD.

2991 uses the same digits as φ(2991).

2992 is the closest integer to 19^e.

2993 is the number of digits of the 22^nd Mersenne prime.

2996 is the number of terms in the 15^th derivative of f(f(f(x))).

2997 = 222 + 999 + 999 + 777.

2998 is a value of n so that n(n+3) is a palindrome.

2999 = 2 + 999 + 999 + 999.

3000 is the number of symmetric arrangements of 7 non-attacking queens on a 7×7 chessboard.