[seqfan] Re: Consecutive sigmas

[Giovanni Resta]

I've added a few terms (one that leads to two representations).

Giovanni

On 03/12/2018 09:13 PM, Hugo Pfoertner wrote:
> See https://oeis.org/draft/A300779 and https://oeis.org/draft/A300780 for
> proposed new sequences.
> 
> On Mon, Mar 12, 2018 at 7:30 PM, Emmanuel Vantieghem <
> emmanuelvantieghem at gmail.com> wrote:
> 
>> 2018-03-12 14:40 GMT+01:00 Hugo Pfoertner <yae9911 at gmail.com>:
>>
>>> 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.
>>> and
>>> 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.
>>>
>>
>>
>>> There is one more occurrence of consecutive odd values of sigma below
>> 10^8
>>> :
>>
>> 38152387 = sigma(15069924), 38152389 = sigma(23011209) ;
>> the number between them is not a sigma value.
>>
>> Emmanuel Vantieghem
>>
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>>
> 
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