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%I #9 Nov 28 2016 20:57:25
%S 2,15,713,82481,17926289,6251997081,3199183099305,2256926363091921,
%T 2099642392012962209,2490468291041882743721,3668423635534285779378041,
%U 6569558349739213693016437665
%N arctanh(sinh(x)+arctan(x))=2*x+15/3!*x^3+713/5!*x^5+82481/7!*x^7...
%F a(n) ~ (2*n)! / r^(2*n+1), where r = 0.5079168569437311537765199369846945055215... is the root of the equation sinh(r)+arctan(r) = 1. - _Vaclav Kotesovec_, Feb 05 2015
%t nn = 20; Table[(CoefficientList[Series[ArcTanh[ArcTan[x] + Sinh[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* _Vaclav Kotesovec_, Feb 05 2015 *)
%K nonn
%O 0,1
%A Patrick Demichel (patrick.demichel(AT)hp.com)
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