271617

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...), t = (primes).at n=31A024597
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (F(2), F(3), F(4), ...), t = (primes).at n=30A025111
• Table T(n,k) = sum over all set partitions of n of number at index k.at n=47A120057
• Number of ways to place zero or more nonadjacent 1,0 2,0 2,1 2,2 3,1 4,1 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155265