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A012178 cos(tan(arctanh(x)))=1-1/2!*x^2-15/4!*x^4-561/6!*x^6-38623/8!*x^8... 0
1, -1, -15, -561, -38623, -4206881, -661302639, -140958927825, -38921417469119, -13433349471318337, -5625858245527551439, -2783882722627688439921, -1585166024021465157765535 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..12.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Cos[Tan[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jun 17 2014 *)

CROSSREFS

Sequence in context: A255956 A115918 A110840 * A012229 A212931 A027462

Adjacent sequences:  A012175 A012176 A012177 * A012179 A012180 A012181

KEYWORD

sign

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

STATUS

approved

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Last modified October 16 03:37 EDT 2019. Contains 328040 sequences. (Running on oeis4.)