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 A013521 Numerator of [x^(2n)] in the Taylor expansion cos(cosec(x)-cot(x))= 1-x^2/8 -7*x^4/384 -97*x^6/46080 -2063*x^8/10321920 -17803*x^10/1238630400 -.... 2

%I

%S 1,-1,-7,-97,-2063,-17803,-250781,166831871,43685848289,447550424579,

%T 84677077231169,11657476758734011,28924058075775365981,

%U 44287070229737735633567,305190813989360271816409

%N Numerator of [x^(2n)] in the Taylor expansion cos(cosec(x)-cot(x))= 1-x^2/8 -7*x^4/384 -97*x^6/46080 -2063*x^8/10321920 -17803*x^10/1238630400 -....

%C The e.g.f of x/2, cos(cosec(x)-cot(x)) = 1 -1*x^2/(2^2*2!) -7*x^4/(2^4*4!) -97*x^6/(2^6*6!) -2063*x^8/(2^8*8!) -..., is apparently covered by A003710.

%H G. C. Greubel, <a href="/A013521/b013521.txt">Table of n, a(n) for n = 0..125</a>

%t Numerator[Take[CoefficientList[Series[Cos[Csc[x] - Cot[x]], {x, 0, 25}], x], {1, -1, 2}]] (* _G. C. Greubel_, Nov 12 2016 *)

%K sign,frac

%O 0,3

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

%E Name edited by _R. J. Mathar_, Dec 19 2011

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Last modified December 1 05:02 EST 2022. Contains 358454 sequences. (Running on oeis4.)