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%I #17 Nov 13 2016 06:58:09
%S -1,7,-17,913,-93959,9405719,-8909477,211410621413,-6740064210937,
%T 2805742760628347,-761503407533329723,340317674208644677253,
%U -38791272133810800467,1468818906393936912860264741
%N Numerator of the coefficient [x^(2n+1)] of the Taylor series arctan(cosec(x) - coth(x)).
%H G. C. Greubel, <a href="/A013540/b013540.txt">Table of n, a(n) for n = 0..200</a>
%e -x/6 + 7*x^3/162 - 17*x^5/13608 + 913*x^7/1224720 - 93959*x^9/1745960832 + ...
%t Numerator[Take[CoefficientList[Series[ArcTan[Csc[x] - Coth[x]], {x,0,26}], x], {2, -1, 2}]] (* _G. C. Greubel_, Nov 13 2016 *)
%K sign,frac
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)
%E Name edited by _R. J. Mathar_, Dec 21 2011