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

A378778

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

Terms

    a(0) =0a(1) =6a(2) =240a(3) =6048a(4) =126720a(5) =2402400a(6) =42771456a(7) =729308160a(8) =12049956864a(9) =194372006400

External references