Expansion of e.g.f. 1 + x*arctanh(x), even powers only.

A166356

Expansion of e.g.f. 1 + x*arctanh(x), even powers only.

Terms

    a(0) =1a(1) =2a(2) =8a(3) =144a(4) =5760a(5) =403200a(6) =43545600a(7) =6706022400

External references