5x5 board with n in all cells
Source: Serbia JBMO TST 2022 P4
June 1, 2022
combinatorics
Problem Statement
Initially in every cell of a board is the number . In one move you may take any cell of this board and add to it and all of its adjacent cells (two cells are adjacent if they share an edge). After a finite number of moves, number is written in all cells. Find all possible values of .