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A009430 Expansion of log(1+x)/cosh(log(1+x)). 0

%I

%S 0,1,-1,-1,12,-56,180,-204,-2688,26496,-103680,-679680,18627840,

%T -229063680,1990759680,-12036729600,40874803200,-365550796800,

%U 21248859340800,-696906569318400,16303221817344000,-317662379016192000

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

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

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

%t CoefficientList[Series[(2*(1 + x)*Log[1 + x])/(1 + (1 + x)^2), {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Jan 23 2015 *)

%K sign,easy

%O 0,5

%A _R. H. Hardin_

%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997

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Last modified September 16 18:26 EDT 2021. Contains 347473 sequences. (Running on oeis4.)