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sin(sec(x)*arctanh(x))=x+4/3!*x^3+20/5!*x^5-1024/7!*x^7-147568/9!*x^9...
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%I #6 Feb 15 2022 13:23:08

%S 1,4,20,-1024,-147568,-19148736,-2934842560,-551525234688,

%T -127249126657792,-35789287036394496,-12158191126869847040,

%U -4941201795126314303488,-2379230211581147229286400

%N sin(sec(x)*arctanh(x))=x+4/3!*x^3+20/5!*x^5-1024/7!*x^7-147568/9!*x^9...

%t With[{nn=30},Take[CoefficientList[Series[Sin[Sec[x]ArcTanh[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Feb 15 2022 *)

%K sign

%O 0,2

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