Expansion of e.g.f. cos(x)*cos(tanh(x)), even powers only.

A009100

Expansion of e.g.f. cos(x)*cos(tanh(x)), even powers only.

Terms

    a(0) =1a(1) =-2a(2) =16a(3) =-328a(4) =11712a(5) =-638720a(6) =49459840a(7) =-5159926528a(8) =697030680576

External references