G.f. satisfies: A(A(x)) = (1+x)^2*A(x).

Terms

a(0) =0a(1) =1a(2) =2a(3) =-3a(4) =18a(5) =-150a(6) =1518a(7) =-17541a(8) =223782a(9) =-3087948a(10) =45470022a(11) =-707810715a(12) =11569008816a(13) =-197540043324