A009167 - OEIS

%I #10 Feb 11 2015 12:23:06

%S 1,1,21,717,38857,3158329,363525789,56250039237,11210469917713,

%T 2783865475754737,840008000833503141,302092032859131150141,

%U 127513257396264637784281,62381091849825754078253353

%N Expansion of cosh(tan(x)/cos(x)).

%t With[{nn=30},Take[CoefficientList[Series[Cosh[Tan[x]/Cos[x]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Feb 11 2015 *)

%K nonn

%O 0,3

%A _R. H. Hardin_

%E Extended and signs tested Mar 15 1997 by _Olivier Gérard_.

%E Previous Mathematica program replaced by _Harvey P. Dale_, Feb 11 2015