31500

Appears in sequences

• Expansion of e.g.f. exp(-x^4/4)/(1-x).at n=8A000138
• Number of spanning trees in C_4 X P_n.at n=2A003753
• Apéry numbers: n^3*C(2n,n).at n=5A005429
• Unitary harmonic numbers (those for which the unitary harmonic mean is an integer).at n=16A006086
• Number of nonseparable toroidal tree-rooted maps with n + 2 edges and n + 1 vertices.at n=13A006414
• Number of tree-rooted toroidal maps with 2 faces and n vertices and without separating loops.at n=3A006439
• Orders of non-cyclic simple groups (divided by 4).at n=32A008976
• Numbers k such that sigma(k)+1 is a square and sets a new record for such squares.at n=42A063729
• Triangle read by rows: T(n,m) = number of graphs on n labeled nodes, with m components of size = order. Also number of graphs on n labeled nodes with m unicyclic components.at n=47A106239
• Numbers n>9 such that n=Abs[(c+d_1)*(c+d_2)*...*(c+d_k)] where d_1 d_2 ... d_k is the decimal expansion of n and c is an integer constant.at n=36A113756
• a(n) = n*binomial(2*n, n)*Fibonacci(n)^2.at n=5A119700
• a(n) = n^2*binomial(2*n, n)*Fibonacci(n).at n=5A119702
• Triangle T(n,k), the number of permutations on n elements that have no cycles of length k.at n=31A122974
• Moment of inertia of all magic cubes of order n.at n=3A126276
• Coefficient of x^2 in the polynomial (x-p(n))*(x-p(n+1))*(x-p(n+2))*(x-p(n+3)), where p(k) is the k-th prime.at n=18A127348
• a(n) = (1/2)*(n^4 + 11*n^3 + 53*n^2 + 97*n + 54).at n=14A129026
• Odd-indexed terms of A129026.at n=7A129027
• Exponential abundant numbers: integers k for which A126164(k) > k, or equivalently for which A051377(k) > 2k.at n=32A129575
• Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=10.at n=38A135195
• Partition number array, called M31(5), related to A049353(n,m)= |S1(5;n,m)| (generalized Stirling triangle).at n=38A144355