[seqfan] Re: Duplicate sigma values

Max Alekseyev maxale at gmail.com
Sat Jun 20 00:22:27 CEST 2009


On Thu, Jun 18, 2009 at 8:52 PM, <franktaw at netscape.net> wrote:

> Some questions: are there any such values with sigma_0 odd?
> (Equivalently, where n and m are squares.)

Here is an example:

sigma_0(326^2) = sigma_0(407^2) = 9
sigma_1(326^2) = sigma_1(407^2) = 187131

> More generally, what values for sigma_0 can occur?

I guess sigma_0 can be any composite number but it would be hard to (dis)prove.

Regards,
Max




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