Recursive triangular sequence: A(n,k)= A(n - 1, k - 1) + A(n - 1, k) + (3 (-1 + n) (-4 + 3 n))*A(n - 2, k - 1).

A153821

Recursive triangular sequence: A(n,k)= A(n - 1, k - 1) + A(n - 1, k) + (3 (-1 + n) (-4 + 3 n))*A(n - 2, k - 1).