A009387 Expansion of log(1+tanh(tanh(x))).

0, 1, -1, -2, 10, 16, -232, -272, 10064, 7936, -720384, -353792, 78009600, 22368256, -11977120768, -1903757312, 2480763381760, 209865342976, -666957211828224, -29088885112832, 225809770695098368, 4951498053124096

Offset

0,4

Links

Table of n, a(n) for n=0..21.

Mathematica

With[{nn=30}, CoefficientList[Series[Log[1+ Tanh[ Tanh[x]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 08 2012 *)

Crossrefs

Cf. A000182.

Bisections are A000182 and A012240.

Sequence in context: A249153 A276046 A268481 * A305093 A316753 A304809

Adjacent sequences: A009384 A009385 A009386 * A009388 A009389 A009390

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved