E.g.f.: 1 / (1 + x^2/2 + log(1 - x)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =8a(4) =46a(5) =324a(6) =2708a(7) =26424a(8) =295272a(9) =3714600a(10) =51929472a(11) =798610416a(12) =13399081584a(13) =243556758912