E.g.f. A(x) = 1/(2-tan(x)-sec(x)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =14a(4) =87a(5) =676a(6) =6303a(7) =68564a(8) =852387a(9) =11921476a(10) =185259603a(11) =3166825364a(12) =59054916687