A009389 Expansion of log(1+tanh(x))*cosh(x).

0, 1, -1, 3, -4, 5, -1, 7, -64, 9, 1319, 11, -49204, 13, 2653559, 15, -196707424, 17, 19194804719, 19, -2385684870724, 21, 367985503366799, 23, -68980888889771104, 25, 15445553274667315799, 27, -4071626956018456576564, 29

Offset: 0

Author

R. H. Hardin

Keywords

• sign
• easy

Crossrefs

From Johannes W. Meijer, May 24 2009: (Start)

The a(2*n) sequence equals the second left hand column of A160485 divided by two.

(End)

Programs

Mathematica

With[{nn=30},CoefficientList[Series[Log[1+Tanh[x]]*Cosh[x],{x,0,nn}], x]Range[0,nn]!] (* Harvey P. Dale, Mar 09 2012 *)

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997