E.g.f. satisfies A(x) = exp(x*A(x^4)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =121a(6) =721a(7) =2521a(8) =6721a(9) =196561a(10) =3659041a(11) =29993041a(12) =159762241a(13) =1686639241a(14) =60298558321a(15) =987112886761