Combinatorics with prime and chess board
Source: 2024 Turkey EGMO TST P5
February 12, 2024
Prime numbergridcombinatorics
Problem Statement
Let be a given prime number. For positive integers let be unit square sets constructed by choosing exactly one unit square from each of the columns from chess board. If for all and for any duo of unit squares which are located at different columns there exists such that both of these unit squares are in find all duos of in terms of .Note: Here we denote the number of rows by and the number of columns by .