Expansion of e.g.f. (1+x)^(1-x).

Terms

a(0) =1a(1) =1a(2) =-2a(3) =-3a(4) =16a(5) =-10a(6) =-114a(7) =462a(8) =-496a(9) =-2952a(10) =16920a(11) =-31680a(12) =-130008a(13) =1707576a(14) =-14259504a(15) =138375720a(16) =-1652311680a(17) =22238105280a(18) =-321916019904