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

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =13a(5) =41a(6) =196a(7) =862a(8) =5489a(9) =31033a(10) =247006a(11) =1706816a(12) =16302397a(13) =133131649a(14) =1483518128a(15) =13978823146a(16) =178022175361