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

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =31a(6) =97a(7) =309a(8) =1026a(9) =3466a(10) =11964a(11) =41856a(12) =148373a(13) =531233a(14) =1919313a(15) =6986745a(16) =25604367a(17) =94379887a(18) =349702606a(19) =1301729084a(20) =4865680876a(21) =18255350676a(22) =68724316775a(23) =259521249065a(24) =982796892300