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

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =13a(5) =61a(6) =331a(7) =1996a(8) =14449a(9) =109873a(10) =971821a(11) =8995636a(12) =93329941a(13) =1018571269a(14) =12110589583a(15) =151955795356