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A013527 Numerator of [x^(2n)] of the Taylor expansion sec(cosec(x)-cot(x)) = 1+ x^2/8 +13*x^4/384 +397*x^6/46080 +4453*x^8/2064384 + ... . 1

%I

%S 1,1,13,397,4453,24649,12478897,47378857957,11289999097969,

%T 1143069714638779,1293273763150662781,15203530875840895739,

%U 46398798213229213203983,209490216975221386279672393,157153880464155360205476452597

%N Numerator of [x^(2n)] of the Taylor expansion sec(cosec(x)-cot(x)) = 1+ x^2/8 +13*x^4/384 +397*x^6/46080 +4453*x^8/2064384 + ... .

%C The e.g.f. related to x/2, sec(cosec(x)-cot(x)) = 1 + 1*x^2/(2^2*2!) + 13*x^4/(2^4*4!) + 397*x^6/(2^6*6!) + 22265*x^8/(2^8*8!) + ..., is apparently provided by A009010.

%H G. C. Greubel, <a href="/A013527/b013527.txt">Table of n, a(n) for n = 0..200</a>

%t Numerator[Take[CoefficientList[Series[Sec[Csc[x] - Cot[x]], {x,0,50}], x], {1, -1, 2}]] (* _G. C. Greubel_, Nov 12 2016 *)

%K nonn,frac

%O 0,3

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

%E Name edited by _R. J. Mathar_, Dec 20 2011

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Last modified April 22 14:20 EDT 2021. Contains 343177 sequences. (Running on oeis4.)