E.g.f.: exp(-x/(1 - x)) / (1 - 2*x).

Terms

a(0) =1a(1) =1a(2) =3a(3) =17a(4) =137a(5) =1389a(6) =16819a(7) =236557a(8) =3792753a(9) =68326073a(10) =1366917731a(11) =30074632521a(12) =721798881913