G.f.: A(x) = x*exp( Sum_{n>=1} A(A(x^n))/n ).

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =52a(5) =280a(6) =1705a(7) =11275a(8) =80120a(9) =604111a(10) =4798905a(11) =39929804a(12) =346524607a(13) =3125963037a(14) =29233335516a(15) =282788639070