%I #6 May 12 2022 18:21:03
%S -1,-2,14,568,9704,-229712,-35581456,-1790014592,72312646784,
%T 28603722780928,3039116082823424,-154149928667313152,
%U -135793191600734657536,-25782484156469234296832
%N tanh(log(cos(x)))=-1/2!*x^2-2/4!*x^4+14/6!*x^6+568/8!*x^8...
%t With[{nn=30},Take[CoefficientList[Series[Tanh[Log[Cos[x]]],{x,0,nn}],x] Range[0,nn]!,{3,-1,2}]] (* _Harvey P. Dale_, May 12 2022 *)
%K sign
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)