Expansion of E.g.f.: (1 + x)/(1 + x + x^2/2).

Terms

a(0) =1a(1) =0a(2) =-1a(3) =3a(4) =-6a(5) =0a(6) =90a(7) =-630a(8) =2520a(9) =0a(10) =-113400a(11) =1247400a(12) =-7484400a(13) =0a(14) =681080400a(15) =-10216206000a(16) =81729648000a(17) =0a(21) =0