Expansion of tan(tanh(x))*cos(x).

A009715

Expansion of tan(tanh(x))*cos(x).

Terms

    a(0) =1a(1) =-3a(2) =-3a(3) =273a(4) =-5159a(5) =-62139a(6) =16414101a(7) =-1357293927a(8) =59192332081

External references