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

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =1a(5) =0a(6) =2a(7) =5a(8) =3a(9) =5a(10) =21a(11) =28a(12) =26a(13) =84a(14) =180a(15) =207a(16) =385a(17) =990a(18) =1562a(19) =2288a(20) =5278a(21) =10439a(22) =15925a(23) =30212a(24) =64738a(25) =112268a(26) =192780a(27) =396338a(28) =761634a(29) =1317840