IMO 2021 Shortlist N6
Determine all integers n ě 2 with the following property: every n pairwise distinct integers whose sum is not divisible ...
Category: Number Theory
Problem
Determine all integers n ě 2 with the following property: every n pairwise distinct
integers whose sum is not divisible by n can be arranged in some order a1, a2, ..., an so that
n divides 1 ¨a1 2 ¨a2 ¨¨¨`n ¨an.