Number of lower triangles of an n X n -1..1 array with all row and column sums zero.
A195515
Number of lower triangles of an n X n -1..1 array with all row and column sums zero.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =15a(4) =199a(5) =6247a(6) =505623a(7) =105997283a(8) =58923059879
External references
- oeis: A195515