G.f. A(x) satisfies A(x) = 1+Sum_{j=0 to infinity} ((1 + x^(j+1)*A(x))^a_j-1).

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =42a(6) =133a(7) =433a(8) =1455a(9) =4958a(10) =17247a(11) =60502a(12) =215353a(13) =770865a(14) =2789365a(15) =10134529a(16) =37130526a(17) =136451349a(18) =504837219a(19) =1872121732a(20) =6980767968a(21) =26078614284a(22) =97872756530a(23) =367861581953