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

Terms

a(0) =1a(1) =1a(2) =0a(3) =0a(4) =12a(5) =60a(6) =240a(7) =1680a(8) =15120a(9) =136080a(10) =1330560a(11) =14636160a(12) =176299200a(13) =2291889600a(14) =32069157120a(15) =481037356800