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

Terms

a(0) =1a(1) =0a(2) =0a(3) =3a(4) =0a(5) =15a(6) =180a(7) =105a(8) =5040a(9) =46305a(10) =132300a(11) =3752595a(12) =33679800a(13) =243378135a(14) =5565940380a(15) =56191160025a(16) =712410098400