bw in nxn chessboard so that in every 2x2 both colors have same number
Source: 11th QEDMO p4 Juniors (6-8. 12. 2012) https://artofproblemsolving.com/community/c1512515_qedmo_200507
May 16, 2021
combinatoricsChessboardColoring
Problem Statement
The fields of an chess board are colored black and white, such that in every small -square both colors should be the same number. How many there possibilities are for this?