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

Terms

a(0) =1a(1) =0a(2) =0a(3) =3a(4) =6a(5) =20a(6) =180a(7) =1134a(8) =7980a(9) =71280a(10) =685440a(11) =7165620a(12) =82720440a(13) =1036404720a(14) =13990472496a(15) =202812132600