G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x)^3).

Terms

a(0) =1a(1) =1a(2) =0a(3) =-3a(4) =-3a(5) =17a(6) =45a(7) =-90a(8) =-546a(9) =130a(10) =5832a(11) =7074a(12) =-53625a(13) =-159214a(14) =374517a(15) =2419131a(16) =-728364a(17) =-30011530a(18) =-37519884a(19) =307731042a(20) =940757526a(21) =-2343385995a(22) =-15421126275a(23) =5164279686a(24) =203045257272a(25) =255851517115