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A013540 Numerator of the coefficient [x^(2n+1)] of the Taylor series arctan(cosec(x) - coth(x)). 1
-1, 7, -17, 913, -93959, 9405719, -8909477, 211410621413, -6740064210937, 2805742760628347, -761503407533329723, 340317674208644677253, -38791272133810800467, 1468818906393936912860264741 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..200

EXAMPLE

-x/6 + 7*x^3/162 - 17*x^5/13608 + 913*x^7/1224720 - 93959*x^9/1745960832 + ...

MATHEMATICA

Numerator[Take[CoefficientList[Series[ArcTan[Csc[x] - Coth[x]], {x, 0, 26}], x], {2, -1, 2}]] (* G. C. Greubel, Nov 13 2016 *)

CROSSREFS

Sequence in context: A102266 A113765 A269447 * A153375 A001145 A093139

Adjacent sequences:  A013537 A013538 A013539 * A013541 A013542 A013543

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 7 12:17 EST 2021. Contains 349581 sequences. (Running on oeis4.)