A009370 - OEIS

%I #16 Jun 22 2015 22:22:32

%S 0,1,-1,7,-20,125,-721,5731,-49440,505529,-5716921,72560255,

%T -1009426340,15366052533,-253286287801,4501151653979,-85717611666720,

%U 1742059862631537,-37625735499057361,860703388428813303

%N Expansion of log(1+tan(x))*cosh(x).

%F a(n) ~ (n-1)! * (-1)^(n+1) * (exp(-Pi/4) + exp(Pi/4)) * 2^(2*n-1) / Pi^n. - _Vaclav Kotesovec_, Jan 23 2015

%t With[{nn=20},CoefficientList[Series[Log[1+Tan[x]]*Cosh[x],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, May 25 2013 *)

%K sign,easy

%O 0,4

%A _R. H. Hardin_

%E Extended with signs by _Olivier Gérard_, Mar 15 1997