A013550 - OEIS

%I #15 Nov 13 2016 15:56:32

%S 1,-1,1,-55,217,-4219,214279,-802171,824071,-109684277,337533513773,

%T -760100160121,8320611986431,-265779449377027,2303253020856673,

%U -417652078505070229,7111553692366818727,-7396136516120375032117

%N Numerator of the coefficient of [x^n] in the Taylor expansion exp(cot(x) - cosech(x)).

%C The inner function is cot(x) - cosech(x) = -x/6 - x^3/24 - x^5/15120 - 17*x^7/40320 - x^9/23950080 - 691*x^11/159667200 - ...

%H G. C. Greubel, <a href="/A013550/b013550.txt">Table of n, a(n) for n = 0..388</a>

%F 1 - x/6 + x^2/72 - 55*x^3/1296 + 217*x^4/31104 - 4219*x^5/6531840 + ...

%t Numerator[Take[CoefficientList[Series[Exp[Cot[x] - Csch[x]], {x,0,40}], x], {1, -1, 1}]] (* _G. C. Greubel_, Nov 13 2016 *)

%Y Cf. A013537, A013541 (bisections?).

%K sign,frac

%O 0,4

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

%E Name edited by _R. J. Mathar_, Dec 21 2011