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

Terms

a(0) =1a(1) =1a(2) =2a(3) =12a(4) =72a(5) =540a(6) =5040a(7) =53760a(8) =658560a(9) =9087120a(10) =139104000a(11) =2343781440a(12) =43078210560a(13) =857676980160