Help with CSES problem Common Divisors

[therealnishuz]

More intuitive explanation for the harmonic series's sum

Hey everyone! I want to talk about something that’s been bothering me for a while. It’s fairly well known that the sum of \frac{n}{i}, 1 \leq i \leq n for any n (that is, \sum\limits_{i=1}^n{\frac{n}{i}}) is O(n\log{n}). This is useful for, for example, finding all divisors of numbers from 1 to n in O(n\log{n}) time. Most editorials just throw this fact at us or say that it can be done with calculus. That’s cool, but what about the majority of people that haven’t learned calculus? I have an al…

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