23280

Appears in sequences

• Difference between n-th prime squared and n-th perfect square.at n=36A106588
• Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity).at n=5A109027
• A triangular sequence of coefficients from a three level exponential expansion function: f(x,t) = log(1 + t)*(1 - t)*exp(x*(t - t^2)).at n=53A137455
• Number of permutation symbols of type *r(n) for hyperbolic archimedean tessellations of rank n.at n=15A142871
• A bisection of A142871.at n=7A142877
• Number of 10 X 10 arrays of squares of integers, symmetric under 90-degree rotation, with all rows summing to n.at n=4A156404
• Number of n X n arrays of squares of integers, symmetric under 90 degree rotation, with all rows summing to 4.at n=9A156436
• Number of line segments connecting exactly 5 points in an n x n grid of points.at n=32A177721
• Numbers k such that sopfr(k + bigomega(k)) = sopfr(k).at n=30A187877
• (Signless) coefficient of x^k in the admittance polynomial of the connected antiregular graph A_n.at n=74A188286
• Number of 3 X n 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=8A207171
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 521", based on the 5-celled von Neumann neighborhood.at n=29A272736
• Numbers k such that Lucas(k) + prime(k) is a prime.at n=8A288794
• Numbers that are not Keith numbers in any base.at n=31A320122
• Number of factorizations of n! into factors > 1 that can be obtained by taking the multiset union of a choice of factorizations of each positive integer from 2 to n into factors > 1.at n=21A321468
• Triangular array read by rows. T(n,k) is the number of n X n matrices over GF(2) such that the sum of the dimensions of their eigenspaces taken over all eigenvalues is k, 0 <= k <= n, n >= 0.at n=11A346201
• a(n) is the number of 2 X 2 matrices over the integers mod n that are invertible mod n for every permutation of their elements.at n=11A367926
• Numbers k such that sigma(k) AND 3*k = 3*k, where AND is bitwise-and, A004198.at n=34A388022