E.g.f.: exp(-x^2/(1+x)).

Terms

a(0) =1a(1) =0a(2) =-2a(3) =6a(4) =-12a(5) =0a(6) =240a(7) =-2520a(8) =21840a(9) =-181440a(10) =1481760a(11) =-11642400a(12) =80498880a(13) =-311351040a(14) =-4739454720a(15) =183437654400