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A009427 Expansion of log(1+x)/cos(tan(x)). 1

%I

%S 0,1,-1,5,-12,109,-405,4913,-24976,372633,-2419425,42646845,

%T -338219244,6863821509,-64452230661,1478191260393,-16062969072000,

%U 410493211996977,-5072547848554017,142840036992492789,-1979718755185227180

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

%H Vaclav Kotesovec, <a href="/A009427/b009427.txt">Table of n, a(n) for n = 0..446</a>

%H Vaclav Kotesovec, <a href="/A009427/a009427.jpg">Graph - asymptotic ratio</a>

%F a(n) ~ (n-1)! * (-1)^(n+1) / cos(tan(1)) * (1 + tan(tan(1)) / ((cos(1))^2*n)). - _Vaclav Kotesovec_, Jan 27 2015

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

%t CoefficientList[Series[Log[1 + x]*Sec[Tan[x]], {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Jan 24 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 August 3 15:54 EDT 2021. Contains 346439 sequences. (Running on oeis4.)