Expansion of e.g.f. 1/(1 - exp(x) + exp(2*x)).

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =5a(4) =11a(5) =-91a(6) =-301a(7) =3485a(8) =15371a(9) =-228811a(10) =-1261501a(11) =22951565a(12) =151846331a(13) =-3264973531a(14) =-25201039501a(15) =625232757245