MathDB
4x4 table and 16 squares

Source: JBMO 2008 Problem 4

June 25, 2008
linear algebramatrixvectorcombinatorics proposedcombinatorics

Problem Statement

A 4×4 4\times 4 table is divided into 16 16 white unit square cells. Two cells are called neighbors if they share a common side. A move consists in choosing a cell and the colors of neighbors from white to black or from black to white. After exactly n n moves all the 16 16 cells were black. Find all possible values of n n.