MathDB
numbers 1-9 in a 3x3 grid

Source: Canada Repêchage 2023/2 CMOQR

March 25, 2024
combinatorics

Problem Statement

How many ways are there to fill a 3×33 \times 3 grid with the numbers 11, 22, 33, 44, 55, 66, 77, 88, and 99, such that the set of three elements in every row and every column form an arithmetic progression in some order? (Each number must be used exactly once)
Back to ProblemsView on AoPS