22050

Appears in sequences

• Pentagonal pyramidal numbers: a(n) = n^2*(n+1)/2.at n=35A002411
• Number of n-step walks on square lattice.at n=9A002900
• Degrees of irreducible representations of Held group He.at n=31A003912
• Theta series of A_6 lattice.at n=20A008446
• Even pentagonal pyramidal numbers.at n=26A015224
• Words over signatures (derived from multisets and multinomials).at n=48A035796
• Words over signatures (derived from multisets and multinomials).at n=33A035796
• Number of functions from a set to itself such that the sizes of the preimages of the individual elements in the range form the n-th partition in Abramowitz and Stegun order.at n=35A049009
• Number of functions from a set to itself such that the sizes of the preimages of the individual elements in the range form the n-th partition in Abramowitz and Stegun order.at n=37A049009
• a(n) = 18*(n - 2)*(2*n - 5).at n=25A060787
• a(n) = prime(n)^2 - prime(n+1).at n=34A062235
• Numbers m such that N = (am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,61.at n=2A065698
• Numbers k such that 2k-1 divides 2^k-1.at n=16A081856
• Group the natural numbers such that the n-th group sum is divisible by the n-th triangular number: (1), (2, 3, 4), (5, 6, 7), (8, 9, 10, 11, 12), (13, 14, 15, 16, 17), (18, 19, 20, 21, 22, 23, 24), ... Sequence contains the group sum.at n=34A086500
• Triangle T(n,k), 0<=k<=n, read by rows, defined by : T(0,0) = 1, T(n,k) = 0 if n<k or if k<0, T(n,k) = k*T(n-1, k-1) + (2n-2k-1)*T(n-1, k).at n=31A108032
• Third column (m=2) of unsigned triangle A111595.at n=5A111602
• One half of third column (k=2) of triangle A111999.at n=3A112000
• a(1)=1, a(n) = Product_{k=2..n} P(k), where P(k) is the largest prime <= k.at n=7A118455
• a(n) = (n!)^2/phi(n!), where phi is Euler's totient function.at n=6A123476
• Interlacing n^3/2 and n^2(n + 1)/2.at n=34A130656