G.f. satisfies A(x) = 1 + x * (1 + x^3)^2 * A(x * (1 + x^3)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =6a(6) =10a(7) =16a(8) =37a(9) =85a(10) =175a(11) =365a(12) =865a(13) =2090a(14) =4826a(15) =11447a(16) =28797a(17) =73086a(18) =183422a(19) =471462a(20) =1249792a(21) =3329832a(22) =8898534a(23) =24244771a(24) =67210802a(25) =187336493a(26) =526399475a(27) =1501301887a(28) =4329346255a(29) =12565028776