Expansion of e.g.f.: arctanh(exp(x)-sec(x)).

Terms

a(0) =0a(1) =1a(2) =0a(3) =3a(4) =-4a(5) =45a(6) =-180a(7) =1743a(8) =-13704a(9) =135705a(10) =-1613160a(11) =18065883a(12) =-276222604a(13) =3655783365a(14) =-65652672540