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A009424 Expansion of log(1+x)/cos(log(1+x)). 1

%I

%S 0,1,-1,5,-24,154,-1170,10394,-105392,1201524,-15210180,211691380,

%T -3212711040,52801793160,-934299180360,17708685967400,

%U -357960437635200,7686847410694800,-174756587308650000,4193327411934706000

%N Expansion of log(1+x)/cos(log(1+x)).

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

%t Log[ 1+x ]/Cos[ Log[ 1+x ] ]

%t CoefficientList[Series[Log[1 + x]*Sec[Log[1 + 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 GĂ©rard_, Mar 15 1997

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Last modified June 15 21:52 EDT 2021. Contains 345053 sequences. (Running on oeis4.)