The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A320024 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A320024

The odd part of those numbers which divide the sum of their divisors (A007691).
(history; published version)

#22 by Michel Marcus at Sat Oct 31 01:39:59 EDT 2020

STATUS

reviewed

approved

#21 by Hugo Pfoertner at Fri Oct 30 19:10:12 EDT 2020

STATUS

proposed

reviewed

#20 by Peter Luschny at Fri Oct 30 18:02:31 EDT 2020

STATUS

editing

proposed

#19 by Peter Luschny at Fri Oct 30 18:01:48 EDT 2020

LINKS

BYU Computational Number Theory Group, <a href="https://arxiv.org/abs/2006.10697">Odd, spoof perfect factorizations</a>, arXiv:2006.10697 [math.NT], 2020.

STATUS

proposed

editing

#18 by Peter Luschny at Fri Oct 30 17:50:43 EDT 2020

STATUS

editing

proposed

#17 by Peter Luschny at Fri Oct 30 17:48:54 EDT 2020

COMMENTS

Note that John Voight's 'spoof odd perfect number' 22017975903 is included. - Peter Luschny, Oct 30 2020

LINKS

J. Voight, <a href="https://math.dartmouth.edu/~jvoight/articles/opn-mass-rev-060211.pdf">On the nonexistence of odd perfect numbers</a>.

STATUS

approved

editing

#16 by Vaclav Kotesovec at Sun Oct 14 05:04:02 EDT 2018

STATUS

editing

approved

#15 by Vaclav Kotesovec at Sun Oct 14 05:03:31 EDT 2018

MATHEMATICA

A007691 = Select[Range[1000000], Divisible[DivisorSigma[1, #], #] &]; Table[A007691[[n]]/2^IntegerExponent[A007691[[n]], 2], {n, 1, Length[A007691]}] (* Vaclav Kotesovec, Oct 14 2018 *)

STATUS

approved

editing

#14 by Alois P. Heinz at Thu Oct 04 19:15:53 EDT 2018

STATUS

editing

approved

#13 by Alois P. Heinz at Thu Oct 04 19:15:50 EDT 2018

LINKS

Alois P. Heinz, <a href="/A320024/b320024.txt">Table of n, a(n) for n = 1..1600</a>

STATUS

approved

editing