login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A013553 Numerator of [x^(2n+1)] of the Taylor expansion -arcsin(cot(x)-coth(x)). 1
2, 4, 8, 272, 15640, 103504, 203248, 4712878048, 994787896, 29947918028368, 19403266491914896, 44494589501437664, 1343012003853467792, 940284256279455687458272, 18264529537961367195872, 13625209118796335138813851456 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

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

EXAMPLE

2*x/3 +4*x^3/81 +8*x^5/567 +272*x^7/76545 +15640*x^9/13640319 +...

MATHEMATICA

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

CROSSREFS

Sequence in context: A033555 A130134 A082613 * A061089 A067499 A135212

Adjacent sequences:  A013550 A013551 A013552 * A013554 A013555 A013556

KEYWORD

nonn,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 | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 21 06:31 EST 2017. Contains 294989 sequences.