Expansion of e.g.f.: -1/(1+x-x^3).

Terms

a(0) =-1a(1) =1a(2) =-2a(3) =0a(4) =24a(5) =-240a(6) =1440a(7) =-5040a(8) =-40320a(9) =1088640a(10) =-14515200a(11) =119750400a(12) =0a(13) =-24908083200a(14) =610248038400