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MathNet 2004 — Part 02 Question 170

Math Olympiad Vault · MathNet 2004 — Part 02

Question 170

Prove that
$$
\frac{\sigma(1)}{1}+\frac{\sigma(2)}{2}+\frac{\sigma(3)}{3}+\cdots+\frac{\sigma(n)}{n} \leq 2 n
$$
for every positive integer $n$.