E.g.f.: 1 / ((sec(x) + tan(x)) * (1 - x)).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =9a(5) =29a(6) =235a(7) =1373a(8) =12369a(9) =103385a(10) =1084371a(11) =11574289a(12) =141594233a(13) =1818356773a(14) =25656355803a(15) =382941579733