n-th derivative of sec(x)^tanh(x) at x=0.

Terms

a(0) =1a(1) =0a(2) =0a(3) =3a(4) =0a(5) =-10a(6) =90a(7) =308a(8) =-1680a(9) =1560a(10) =123480a(11) =-43032a(12) =-5151960a(13) =40323920a(14) =538618080a(15) =-3880887592a(16) =-32036135040a(17) =815589894720