[seqfan] Re: sigma(n) =

Olivier Gerard olivier.gerard at gmail.com
Fri Nov 20 10:59:45 CET 2015


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In my opinion,  the sequence 5)  sigma(n) = 2*sigma(n - 2)   is interesting
and you should submit it.

Best Regards,

Olivier


On Wed, Nov 11, 2015 at 8:07 AM, юрий герасимов <2stepan at rambler.ru> wrote:

> Dear SeqFans, also n such that:
>
> 4) sigma(n) = 1*sigma(n - 1): 15, 207, 958, ... (in OEIS is A231546)
>
> 5) sigma(n) = 2*sigma(n - 2): 120. 1560, 2940, 17760, 19920, 32220, 33840,
> 55965,
> 710040, 186780, 308040, 511500, 523776, 553500, 699360, 838215, ...
>
> 6) sigma(n) = 3*sigma(n - 3); 6, 30240, 242320, 3116960, 4044090, 6902280,
> ...
>
> 7) sigma(n) = 4*sigma(n - 4): 6, ....
>
> 8) sigma(n) = 5*sigma(n - 5). ?
>
> юрий герасимов.
>
>  09.11.2015, 18:42:11 пользователь юрий герасимов (2stepan at rambler.ru)
>  написал:
>
>
>
>  Dear SeqFans, n such that:
>
>  1) sigma(n) = sigma(n - 2) + sigma(n + 2): 5160, 19080, 210336, 606420,
>  1146720, 2382480, 3409140, ...
>
>  2) sigma(n) = sigma(n - 2) - sigma(n + 2): 12812942, 45553367, 95028362,
> ...
>
>  3) sigma(n) = sigma(n + 2) - sigma(n - 2): 358, 62494, 342238, 410638,
>  8219473, 58463494, ...
>
>  The sequences are "of general interest"?
>
>  Best regards, JSG
>
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