Triangle read by rows: T(n,k) (n >= 0, 0<=k<=n) gives number of {0,1} n X n matrices with all row and column sums equal to k.
1, 1, 1, 1, 2, 1, 1, 6, 6, 1, 1, 24, 90, 24, 1, 1, 120, 2040, 2040, 120, 1, 1, 720, 67950
1 seqfan posts
Sun Jan 18 02:59:08 CET 2009 [seqfan] Re: Two Sequences Related To Permutations of (1,2,...,n)