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A012208 tanh(arctan(arctan(x)))=x-6/3!*x^3+184/5!*x^5-13136/7!*x^7... 0

%I

%S 1,-6,184,-13136,1679488,-335723264,96492653568,-37665610561536,

%T 19158060131778560,-12304193595906129920,9734505561510299566080,

%U -9299736312230986726768640,10553185490408007072659537920

%N tanh(arctan(arctan(x)))=x-6/3!*x^3+184/5!*x^5-13136/7!*x^7...

%t With[{nn=30},Take[CoefficientList[Series[Tanh[ArcTan[ArcTan[x]]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Nov 15 2014 *)

%K sign

%O 0,2

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

%E Definition clarified by _Harvey P. Dale_, Nov 15 2014

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Last modified October 31 00:25 EDT 2020. Contains 338095 sequences. (Running on oeis4.)