List questions from divisor-sum

Published on 08 Dec 2018 - 18:14

794

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About The Sum of Positive Divisors of $n$

Published on 25 Mar 2026 - 6:24

336

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Sum of divisors of $n$ less than $k$

Published on 11 Dec 2018 - 22:24

68

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On an interesting assertion in the OeisWiki page on multiply-perfect numbers

Published on 24 Dec 2018 - 9:44

106

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Is it true that $\gcd(s(p^k), D(p^k)) = 1$?

Published on 25 Dec 2018 - 9:40

109

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Limiting value of $\frac{\sigma(n)}{n}$

Published on 26 Dec 2018 - 5:54

402

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Are there infinitely many sets of relatively prime numbers with equal number and sum of divisors?

Published on 26 Dec 2018 - 16:37

240

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About the equation $x^2+y^2+z^2+2t^2=n$

Published on 25 Mar 2026 - 4:40

203

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On Yanqi Xu's 2016 joint undergraduate math research project with Dr. Judy Holdener at Kenyon College

Published on 25 Mar 2026 - 7:54

68

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If $q \equiv k \equiv 1 \pmod 4$, is it necessarily true that $\gcd\bigg(\sigma(q^k),\sigma(q^{(k-1)/2})\bigg)=1$?

Published on 25 Mar 2026 - 7:54

337

Views

On Basak's "Bounds On Factors Of Odd Perfect Numbers"

Published on 25 Mar 2026 - 7:52

59

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On some inequalities relating the special/Euler prime and non-Euler part of odd perfect numbers

Published on 09 Jan 2019 - 6:02

77

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Can this inequality regarding odd perfect numbers be improved?

Published on 09 Jan 2019 - 11:46

92

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Truncated sum of divisors bound

Published on 25 Mar 2026 - 6:19

51

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How to simplify $2 q^{\frac{k-1}{2}} n^2 - \sigma(q^{\frac{k-1}{2}})\sigma(n^2)$

Published on 25 Mar 2026 - 7:54

List Question

A bridge between the sum of the divisors and the Totient function

About The Sum of Positive Divisors of $n$

Sum of divisors of $n$ less than $k$

On an interesting assertion in the OeisWiki page on multiply-perfect numbers

Is it true that $\gcd(s(p^k), D(p^k)) = 1$?

Limiting value of $\frac{\sigma(n)}{n}$

Are there infinitely many sets of relatively prime numbers with equal number and sum of divisors?

About the equation $x^2+y^2+z^2+2t^2=n$

On Yanqi Xu's 2016 joint undergraduate math research project with Dr. Judy Holdener at Kenyon College

If $q \equiv k \equiv 1 \pmod 4$, is it necessarily true that $\gcd\bigg(\sigma(q^k),\sigma(q^{(k-1)/2})\bigg)=1$?

On Basak's "Bounds On Factors Of Odd Perfect Numbers"

On some inequalities relating the special/Euler prime and non-Euler part of odd perfect numbers

Can this inequality regarding odd perfect numbers be improved?

Truncated sum of divisors bound

How to simplify $2 q^{\frac{k-1}{2}} n^2 - \sigma(q^{\frac{k-1}{2}})\sigma(n^2)$

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