E.g.f. satisfies A(x) = exp(x*A(x^3)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =25a(5) =121a(6) =361a(7) =3361a(8) =42001a(9) =275185a(10) =1819441a(11) =30777121a(12) =371238121a(13) =9284332201a(14) =131442054745