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A009392 Expansion of e.g.f.: log(1+tanh(x))/cosh(x). 1
0, 1, -1, -3, 8, 25, -121, -427, 3128, 12465, -124921, -555731, 7158128, 35135945, -557749921, -2990414715, 56767019408, 329655706465, -7316056402321, -45692713833379, 1164842760597368, 7777794952988025, -224574978081433321 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..22.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Log[1+Tanh[x]]/Cosh[x], {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, Oct 06 2014 *)

CROSSREFS

Sequence in context: A004205 A268114 A097713 * A130648 A061812 A009452

Adjacent sequences:  A009389 A009390 A009391 * A009393 A009394 A009395

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Oct 06 2014

STATUS

approved

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Last modified September 26 19:57 EDT 2021. Contains 347672 sequences. (Running on oeis4.)