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

A009719

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

Terms

    a(0) =1a(1) =3a(2) =17a(3) =371a(4) =11329a(5) =398211a(6) =31717649a(7) =2487281075a(8) =257775723265

External references