G.f. satisfies A(x) = 1 + x*(1 + x*A(x)^3)^5.

Terms

a(0) =1a(1) =1a(2) =5a(3) =25a(4) =160a(5) =1075a(6) =7671a(7) =56760a(8) =431865a(9) =3357790a(10) =26558520a(11) =213032988a(12) =1728808700a(13) =14168337265a(14) =117096909495a(15) =974842628790