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%I #6 Nov 15 2014 17:34:25
%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