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%I #6 Jun 28 2021 19:16:03
%S 2,20,256,4832,42496,1467392,62836736,42790912,2535587840,
%T 170851041280,3070050172928,256460544016384,4697678227177472,
%U 52001663422038016,5598478396465086464,647670579588837146624,2427980359983876276224,9138219784535816536064,1277040945143933271277568
%N Numerator of Sum_{k=1..2n+1} 2^k/k.
%e 2, 20/3, 256/15, 4832/105, 42496/315, 1467392/3465, 62836736/45045, 42790912/9009, 2535587840/153153, 170851041280/2909907, 3070050172928/14549535, 256460544016384/334639305, 4697678227177472/1673196525, 52001663422038016/5019589575, ...
%t Take[Numerator[Accumulate[Table[2^k/k,{k,51}]]],{1,-1,2}] (* _Harvey P. Dale_, Jun 28 2021 *)
%Y Cf. A229726, A108866.
%K nonn,frac
%O 0,1
%A _N. J. A. Sloane_, Sep 28 2013
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