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A012172 sec(tan(tanh(x)))=1+1/2!*x^2+5/4!*x^4+13/6!*x^6+41/8!*x^8... 0

%I

%S 1,1,5,13,41,1529,-168851,14151621,-1169749807,65719458673,

%T 5735813087573,-3489760303917315,1000904582588332537,

%U -229661980583327166359,41111046331054702141117,-2494708337718975104154187,-2794803495926284988945714271

%N sec(tan(tanh(x)))=1+1/2!*x^2+5/4!*x^4+13/6!*x^6+41/8!*x^8...

%t With[{nn=30},Take[CoefficientList[Series[Sec[Tan[Tanh[x]]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Oct 15 2013 *)

%K sign

%O 0,3

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

%E More terms from _Harvey P. Dale_, Oct 15 2013

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Last modified September 1 04:07 EDT 2014. Contains 246282 sequences.