a(n) = n^2 * 4^n * binomial(3*n, n).

A378779

a(n) = n^2 * 4^n * binomial(3*n, n).

Terms

    a(0) =0a(1) =12a(2) =960a(3) =48384a(4) =2027520a(5) =76876800a(6) =2737373184a(7) =93351444480

External references