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

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =1a(5) =1a(6) =0a(7) =0a(8) =1a(9) =3a(10) =2a(11) =0a(12) =1a(13) =6a(14) =10a(15) =5a(16) =1a(17) =10a(18) =30a(19) =35a(20) =15a(21) =15a(22) =70a(23) =140a(24) =127a(25) =63a(26) =140a(27) =420a(28) =631a(29) =490