%I #8 Feb 04 2015 04:26:58
%S 1,-4,76,-3536,317392,-47590720,10785422272,-3441103532288,
%T 1468657322465536,-807408622401283072,555453404529224756224,
%U -467352773254586231115776,472081158536303158224572416
%N arcsinh(sin(tanh(x)))=x-4/3!*x^3+76/5!*x^5-3536/7!*x^7+317392/9!*x^9...
%H Vaclav Kotesovec, <a href="/A012047/b012047.txt">Table of n, a(n) for n = 0..212</a>
%F a(n) ~ c * (-1)^n * (2*n)! / (sqrt(n) * (arctan(arcsinh(1)))^(2*n)), where c = 1.0522205751764250070089302438417471228756... . - _Vaclav Kotesovec_, Feb 04 2015
%t nn = 20; Table[(CoefficientList[Series[ArcSinh[Sin[Tanh[x]]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* _Vaclav Kotesovec_, Feb 04 2015 *)
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)
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