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

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-2a(4) =8a(5) =8a(6) =112a(7) =656a(8) =5504a(9) =49024a(10) =491264a(11) =5401856a(12) =64826368a(13) =842734592a(14) =11798300672a(15) =176974477312