860017domain: NAppears in sequencesNumber of lower triangles of an n X n -2..2 array with all row and column sums zero.at n=5A195516T(n,k) = Number of lower triangles of an n X n -k..k array with all row and column sums zero.at n=26A195522Number of lower triangles of a 6X6 -n..n array with all row and column sums zero.at n=1A195524