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

Terms

a(0) =1a(1) =0a(2) =-1a(3) =0a(4) =2a(5) =-3a(6) =-4a(7) =30a(8) =-55a(9) =-126a(10) =1190a(11) =-3333a(12) =-4522a(13) =90354a(14) =-417349a(15) =290628a(16) =9897158a(17) =-79200003a(18) =253387112a(19) =981776010a(20) =-18675127711a(21) =120607895430a(22) =-211057884214