a(n) = binomial(n^2 + 3*n, n).

A214400

a(n) = binomial(n^2 + 3*n, n).

Terms

    a(0) =1a(1) =4a(2) =45a(3) =816a(4) =20475a(5) =658008a(6) =25827165a(7) =1198774720a(8) =64276915527

External references