[seqfan] Re: Consecutive sigmas

Hugo Pfoertner yae9911 at gmail.com
Mon Mar 12 14:40:04 CET 2018

The only 4 consecutive values in A002191 I could find are 12, 13, 14, 15 at
the very beginning. Checking through m=10^7 there are two more occurrences
of consecutive odd sums sigma(m) of divisors:
sigma(36)=91, sigma(50)=93, but 92 doesn't occur as sigma.
sigma(241081)=241573, sigma(117128)=241575, 241574 again not in A000203.

Might be interesting if we can find another occurrence of two consecutive
odd sigmas.

Hugo Pfoertner

On Mon, Mar 12, 2018 at 11:58 AM, Frank Adams-Watters via SeqFan <
seqfan at list.seqfan.eu> wrote:

> Are there ever 4 consecutive values in https://oeis.org/A002191 - "
>  Possible values for sum of divisors of n. "?
> Such an instance would have to include two consecutive odd numbers. Are
> there infinitely many such pairs?
> Franklin T. Adams-Watters
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> Seqfan Mailing list - http://list.seqfan.eu/

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