login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 4 14:04 EST 2022. Contains 358558 sequences. (Running on oeis4.)