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A229727 Numerator of Sum_{k=1..2n+1} 2^k/k. 1
2, 20, 256, 4832, 42496, 1467392, 62836736, 42790912, 2535587840, 170851041280, 3070050172928, 256460544016384, 4697678227177472, 52001663422038016, 5598478396465086464, 647670579588837146624, 2427980359983876276224, 9138219784535816536064, 1277040945143933271277568 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..18.

EXAMPLE

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, ...

MATHEMATICA

Take[Numerator[Accumulate[Table[2^k/k, {k, 51}]]], {1, -1, 2}] (* Harvey P. Dale, Jun 28 2021 *)

CROSSREFS

Cf. A229726, A108866.

Sequence in context: A195157 A207151 A272568 * A325409 A155671 A303616

Adjacent sequences:  A229724 A229725 A229726 * A229728 A229729 A229730

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Sep 28 2013

STATUS

approved

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Last modified September 19 00:22 EDT 2021. Contains 347549 sequences. (Running on oeis4.)