Expansion of e.g.f. cos(x)/cos(tan(x)), even powers only.

A009106

Expansion of e.g.f. cos(x)/cos(tan(x)), even powers only.

Terms

    a(0) =1a(1) =0a(2) =8a(3) =216a(4) =12032a(5) =1075328a(6) =140944000a(7) =25464568832

External references