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%I #14 Jun 21 2015 21:48:42
%S 0,1,-2,10,-53,373,-3289,34543,-421994,5884933,-92255061,1606210571,
%T -30754222080,642299748231,-14531152719875,354020726656465,
%U -9240813172692064,257285058656341145,-7611049992188970105
%N Expansion of log(1+log(1+x)*cosh(x)).
%F a(n) ~ (n-1)! * (-1)^(n+1) / (1-exp(-r))^n, where r = 0.8549045967031373719104055170906807819800761165... is the root of the equation 2*exp(-1 + exp(-r)) - r - exp(2/exp(r)-2)*r = 0. - _Vaclav Kotesovec_, Jan 24 2015
%t Log[ 1+Log[ 1+x ]*Cosh[ x ] ]
%t CoefficientList[Series[Log[1 + Cosh[x]*Log[1 + x]], {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Jan 24 2015 *)
%K sign,easy
%O 0,3
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997