Difference between revisions of "2023 APMO Problems/Problem 2"

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==Problem==
 
==Problem==
  
Find all integers <math>n</math> satisfying <math>n \ge 2</math> and <math>\frac{\sigma(n)}{p(n)-1}, in which </math>\sigma(n)<math> denotes the sum of all positive divisors of </math>n<math>, and </math>p(n)<math> denotes the largest prime divisor of </math>n$.
+
Find all integers <math>n</math> satisfying <math>n \ge 2</math> and <math>\frac{\sigma(n)}{p(n)-1}</math>, in which <math>\sigma(n)</math> denotes the sum of all positive divisors of <math>n</math>, and <math>p(n)</math> denotes the largest prime divisor of <math>n</math>.
  
 
==Solution==
 
==Solution==
 
https://youtu.be/xkIm0k1FE-8
 
https://youtu.be/xkIm0k1FE-8

Revision as of 21:51, 19 August 2023

Problem

Find all integers $n$ satisfying $n \ge 2$ and $\frac{\sigma(n)}{p(n)-1}$, in which $\sigma(n)$ denotes the sum of all positive divisors of $n$, and $p(n)$ denotes the largest prime divisor of $n$.

Solution

https://youtu.be/xkIm0k1FE-8