G.f. A(x) satisfies: A(x^2*B(x)) = x^3 - x^4, where A(B(x)) = x.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =18a(5) =57a(6) =192a(7) =666a(8) =2362a(9) =8548a(10) =31422a(11) =116967a(12) =440100a(13) =1671097a(14) =6395116a(15) =24640671a(16) =95511110a(17) =372179427a(18) =1457127788a(19) =5728994316a(20) =22610712406a(21) =89546822784a(22) =355755807944