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

Terms

a(0) =1a(1) =1a(2) =3a(3) =13a(4) =69a(5) =419a(6) =2809a(7) =20353a(8) =157199a(9) =1281993a(10) =10963825a(11) =97828031a(12) =907177801a(13) =8716049417a(14) =86553001779a(15) =886573220093