Number of 2n X n (0,1)-matrices with row sums 2 and column sums 4.

A134648

Number of 2n X n (0,1)-matrices with row sums 2 and column sums 4.

Terms

    a(0) =0a(1) =1a(2) =90a(3) =44730a(4) =56586600a(5) =154700988750

External references