A013544 Numerator of the coefficient [x^(2n+1)] of tanh(cosec(x)-coth(x)).

-1, 7, -1013, 64763, -3009173, 5341411709, -857007547621, 28828641126011, -1030088087041163819, 108508429719458111069, -2005462402042629244533103, 41348510060126079043949299, -132583025047910486114666220223

Offset

0,2

Links

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

Example

-x/6 +7*x^3/162 -1013*x^5/816480 +64763*x^7/88179840 -...

Mathematica

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

Crossrefs

Sequence in context: A349736 A110718 A293142 * A250914 A004807 A139781

Adjacent sequences: A013541 A013542 A013543 * A013545 A013546 A013547

Keyword

sign,frac

Author

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

Extensions

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

Status

approved