Source: Iranian TST 2020, second exam day 2, problem 6
March 12, 2020
number theoryprime numbers
Problem Statement
p is an odd prime number. Find all 2p−1-tuples (x1,x2,…,x2p−1)∈Zp2p−1 such that
i=1∑2p−1xi≡i=1∑2p−1xi2≡⋯≡i=1∑2p−1xi2p−1(modp).Proposed by Ali Partofard