167868

Appears in sequences

• Expansion of 1/sqrt(1-4x/(1-x)^4).at n=7A162478
• Triangle read by rows: T(n,k) is the number of subpermutations of an n-set whose orbits are each of size at most k, and without fixed points. Equivalently, T(n,k) is the number of partial derangements of an n-set each of whose orbits is of size at most k.at n=39A261762