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

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =15a(5) =101a(6) =841a(7) =8267a(8) =93259a(9) =1184693a(10) =16718377a(11) =259403303a(12) =4389247891a(13) =80446526037