2,2

a(m,n) = 2^{-m}\sum_{i = 0}^{n}frac{(-1)^{i}m!n!(2m-2i)!}{i!(m-i)!(n-i)!6^{n-i}% }$

Adjacent sequences: A134644 A134645 A134646 this_sequence A134648 A134649 A134650

Sequence in context: A022062 A107526 A132202 this_sequence A054815 A023744 A054816

nonn

Shanzhen Gao (sgao2(AT)fau.edu), Nov 05 2007

Perhaps "Number of n X n-1 (0,1)-matrices ..." ? - njas