Number of lower triangles of an n X n -4..4 array with all row and column sums zero.

A195518

Number of lower triangles of an n X n -4..4 array with all row and column sums zero.

Terms

    a(0) =1a(1) =1a(2) =9a(3) =369a(4) =121367a(5) =286168923

External references