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A009774 Expansion of e.g.f.: tanh(log(1+tanh(x))). 0
0, 1, -1, -2, 14, -14, -286, 1828, 3464, -130664, 619304, 7421008, -128214736, 153779536, 18052524944, -209102239712, -1370716606336, 63200892286336, -414519986847616, -12766540334296832, 303340786629265664 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..20.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Tanh[Log[1+Tanh[x]]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Aug 17 2012 *)

CROSSREFS

Sequence in context: A307269 A072163 A084674 * A276553 A032933 A194230

Adjacent sequences:  A009771 A009772 A009773 * A009775 A009776 A009777

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified by Harvey P. Dale, Aug 17 2012

STATUS

approved

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Last modified October 23 21:27 EDT 2021. Contains 348217 sequences. (Running on oeis4.)