175203184374
domain: N
Appears in sequences
- Hertzsprung's problem: ways to arrange n non-attacking kings on an n X n board, with 1 in each row and column. Also number of permutations of length n without rising or falling successions.at n=15A002464
- Triangle read by rows: T(n,k) is the number of ways to place k non-attacking kings in each row and column of an n X n board, 0 <= k <= floor(n/4) + [n=1].at n=37A387098