1,3

Number of m X n binary matrices with no zero rows or columns and with k=0..m*n ones is Sum_{i=0..n} (-1)^i*C(n, i)*a(m, n-i, k) where a(m, n, k)=Sum_{i=0..m} (-1)^i*C(m, i)*C((m-i)*n, k).

a(n) = n*(n-1)*(9*n^4+42*n^3+7*n^2-122*n-120)*n!/576. - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 25 2006

A diagonal of triangle A104601.

Cf. A055602.

Sequence in context: A060094 A065951 A008393 this_sequence A109124 A013359 A013355

Adjacent sequences: A055600 A055601 A055602 this_sequence A055604 A055605 A055606

nonn

Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 01 2000