21784

Appears in sequences

• Numbers k such that the number of prime divisors of the k-th Catalan number (counted with multiplicity) divides k.at n=41A121612
• Triangle read by rows: T(n,m) is the number of cyclic permutations of [n] in which m of successive numbers add to a prime. 0<=m<=n, read by rows n>=0.at n=57A132178
• Numbers n with all digits different, such that all of its digits divide n, but none of the nonzero digits not in n divide n.at n=16A133606
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (-1, 1, 0), (0, -1, 1), (0, 1, 0), (1, 1, -1)}.at n=10A148209
• a(n) = Hermite(n,14).at n=3A158545
• The 3rd Hermite Polynomial evaluated at n: H_3(n) = 8*n^3 - 12*n.at n=14A163322
• Total number of inversions in all derangement permutations of [n].at n=7A216239
• Egyptian fraction representation of sqrt(26) (A010481) using a greedy function.at n=3A248253
• Numbers n representable as x*y + x + y, where x >= y > 1, such that all x's and y's in all representation(s) of n are perfect squares.at n=30A258366
• Expansion of Product_{k>=1} 1/(1 - x^prime(k))^2.at n=41A298436
• Number of vertices formed in a square by straight line segments when connecting the n-1 points between each corner that divide each edge into n equal parts to the n-1 points on each of the two adjacent edges of the square.at n=10A358408