G.f. satisfies: A(x) = A(y^2)/(1-y) where y = x*A(x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =34a(5) =131a(6) =542a(7) =2297a(8) =10043a(9) =44722a(10) =202669a(11) =930527a(12) =4321859a(13) =20264186a(14) =95802300a(15) =456152409a(16) =2185541010a(17) =10529301243a(18) =50976432986a(19) =247881491762