G.f. satisfies A(x) = 1 + x*A(x)^3 + x^3*A(x)^4.

Terms

a(0) =1a(1) =1a(2) =3a(3) =13a(4) =62a(5) =318a(6) =1718a(7) =9627a(8) =55437a(9) =326070a(10) =1950630a(11) =11831706a(12) =72597453a(13) =449804148a(14) =2810260317a(15) =17685019893a(16) =111997074910a(17) =713223954540