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%I #14 Jun 22 2015 22:22:56
%S 0,1,-1,7,-20,145,-781,6711,-55040,578465,-6372241,81400295,
%T -1118247140,17017477425,-278763221101,4944906503959,-93847119338720,
%U 1903841305391425,-41033336868850561,937270802152757703
%N Expansion of log(1+tan(x))/cos(x).
%F a(n) ~ (n-1)! * (-1)^(n+1) * 2^(2*n+1/2) / Pi^n. - _Vaclav Kotesovec_, Jan 23 2015
%t Log[ 1+Tan[ x ]]/Cos[ x ]
%t CoefficientList[Series[Log[1 + Tan[x]]*Sec[x], {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Jan 23 2015 *)
%K sign,easy
%O 0,4
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997