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

Terms

a(0) =0a(1) =1a(2) =0a(3) =2a(4) =-4a(5) =20a(6) =-120a(7) =632a(8) =-6704a(9) =44480a(10) =-630240a(11) =5566112a(12) =-91544704a(13) =1063375040a(14) =-19258162560a(15) =283305867392