MathDB
Number theory

Source: IMSC

July 4, 2023
number theoryinequalities

Problem Statement

There are n!n! empty baskets in a row, labelled 1,2,...,n!1, 2, . . . , n!. Caesar first puts a stone in every basket. Caesar then puts 2 stones in every second basket. Caesar continues similarly until he has put nn stones into every nth basket. In other words, for each i=1,2,...,n,i = 1, 2, . . . , n, Caesar puts ii stones into the baskets labelled i,2i,3i,...,n!.i, 2i, 3i, . . . , n!. Let xix_i be the number of stones in basket ii after all these steps. Show that n!n2i=1n!xi2n!n2i=1n1in! \cdot n^2 \leq \sum_{i=1}^{n!} x_i^2 \leq n! \cdot n^2 \cdot \sum_{i=1}^{n} \frac{1}{i}