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Numerator of [x^(2n)] of the Taylor series sec(cot(x)-coth(x))= 1 +2*x^2/9 +10*x^4/243 +2356*x^6/229635 +986*x^8/413343+...
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%I #12 Nov 12 2016 08:12:45

%S 1,2,10,2356,986,36236852,45967324,6310668536,55999847998,

%T 13505508015664052,73561146096203972,1018280445612115249048,

%U 184320514834002228148,30993244629183109104307016

%N Numerator of [x^(2n)] of the Taylor series sec(cot(x)-coth(x))= 1 +2*x^2/9 +10*x^4/243 +2356*x^6/229635 +986*x^8/413343+...

%H Vincenzo Librandi, <a href="/A013557/b013557.txt">Table of n, a(n) for n = 0..100</a>

%t Numerator[Take[CoefficientList[Series[Sec[Cot[x] - Coth[x]], {x, 0, 35}], x], {1, -2, 2}]] (* _Vincenzo Librandi_, Nov 12 2016 *)

%K nonn,frac

%O 0,2

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

%E Name edited by _R. J. Mathar_, Dec 22 2011