Expansion of e.g.f. exp(x + x^2 + x^3).

Terms

a(0) =1a(1) =1a(2) =3a(3) =13a(4) =49a(5) =261a(6) =1531a(7) =9073a(8) =63393a(9) =465769a(10) =3566611a(11) =29998101a(12) =262167313a(13) =2394499693a(14) =23249961099a(15) =233439305401