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

Terms

a(0) =1a(1) =3a(2) =11a(3) =53a(4) =345a(5) =2947a(6) =31411a(7) =400437a(8) =5927921a(9) =99816515a(10) =1882741659a(11) =39310397557a(12) =899919305929