Number of nonnegative integer n X n matrices with row and column sums 2 and sum of entries below the main diagonal n - 1.

A332729

Number of nonnegative integer n X n matrices with row and column sums 2 and sum of entries below the main diagonal n - 1.

Terms

    a(0) =1a(1) =1a(2) =11a(3) =114a(4) =2438a(5) =73120a(6) =3107640a(7) =175157568a(8) =12683256458

External references