Expansion of e.g.f. (1+x) * exp(x^2*(1+x)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =12a(4) =36a(5) =180a(6) =1200a(7) =5880a(8) =42000a(9) =317520a(10) =2147040a(11) =18627840a(12) =160332480a(13) =1357836480a(14) =13457283840a(15) =131026896000