G.f. satisfies: A(x) = x + sum_{n>=1} A(x)^prime(n).

Terms

a(0) =1a(1) =1a(2) =3a(3) =10a(4) =39a(5) =161a(6) =699a(7) =3135a(8) =14425a(9) =67694a(10) =322777a(11) =1559285a(12) =7615406a(13) =37539265a(14) =186525154a(15) =933239667a(16) =4697671339a(17) =23773865938a(18) =120889679621a(19) =617355432767