Expansion of e.g.f. exp( (x * (1+x))^3 ).

Terms

a(0) =1a(1) =0a(2) =0a(3) =6a(4) =72a(5) =360a(6) =1080a(7) =15120a(8) =302400a(9) =3689280a(10) =32659200a(11) =359251200a(12) =6965481600a(13) =133880947200