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A013545 Numerator of the coefficient [x^(2n+1)] of the Taylor series arctanh(cosec(x) - coth(x)). 1
-1, 13, 29, 397, 74927, 2570951, 495301, 2978520989, 879781928617, 1962442468445621, 4485273725677799419, 17810142018975186977 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..200 [Vincenzo Librandi computed the first 100 terms; Terms 101 to 200 computed by G. C. Greubel, Nov 13 2016]

EXAMPLE

-x/6 + 13*x^3/324 + 29*x^5/27216 + 397*x^7/2449440 + 74927*x^9/3491921664 + ... .

MATHEMATICA

Numerator[Take[CoefficientList[Series[ArcTanh[Csc[x] - Coth[x]], {x, 0, 35}], x], {2, -2, 2}]] (* Vincenzo Librandi, Nov 12 2016 *)

CROSSREFS

Sequence in context: A166272 A317897 A195878 * A120273 A104817 A048450

Adjacent sequences:  A013542 A013543 A013544 * A013546 A013547 A013548

KEYWORD

sign,frac

AUTHOR

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

EXTENSIONS

Name edited by R. J. Mathar, Dec 21 2011

STATUS

approved

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Last modified December 6 09:10 EST 2021. Contains 349563 sequences. (Running on oeis4.)