G.f. A(x) satisfies: A(x) = x / exp(2 * Sum_{k>=1} A(x^k) / k).

Terms

a(0) =1a(1) =-2a(2) =5a(3) =-18a(4) =70a(5) =-282a(6) =1179a(7) =-5104a(8) =22634a(9) =-102128a(10) =467637a(11) =-2168208a(12) =10157664a(13) =-48005858a(14) =228607728a(15) =-1095885048a(16) =5284044080a(17) =-25609804110a(18) =124693451466a(19) =-609641464746