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

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =-3a(6) =-50a(7) =-237a(8) =-872a(9) =-2375a(10) =-3522a(11) =11383a(12) =140170a(13) =830999a(14) =3797676a(15) =13901117a(16) =36231696a(17) =12991001a(18) =-656219096a(19) =-5809148691a(20) =-35189341480a(21) =-173155983991a(22) =-699938697650