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

Terms

a(0) =1a(1) =1a(2) =-2a(3) =6a(4) =-30a(5) =184a(6) =-1294a(7) =10034a(8) =-83908a(9) =746006a(10) =-6983600a(11) =68360302a(12) =-696122684a(13) =7345561204a(14) =-80074813040a(15) =899590031932