G.f. satisfies: A(x) = Sum_{n>=0} x^(n(n+1)/2) * A(x)^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =14a(7) =30a(8) =62a(9) =129a(10) =278a(11) =604a(12) =1313a(13) =2883a(14) =6386a(15) =14203a(16) =31733a(17) =71272a(18) =160725a(19) =363670a(20) =825653a(21) =1880351a(22) =4293985a(23) =9830499a(24) =22558939a(25) =51880565a(26) =119552907a(27) =276012657a(28) =638348123a(29) =1478749229