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

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =19a(5) =65a(6) =231a(7) =849a(8) =3193a(9) =12238a(10) =47614a(11) =187578a(12) =746731a(13) =2999264a(14) =12139398a(15) =49463204a(16) =202729889a(17) =835242106a(18) =3457178366a(19) =14369424882a(20) =59949943825a(21) =250967906314