MathDB
bw squares in nxn grid, coloring with limits on 2x2 square coloring

Source: Finland 2015, Problem 4

September 1, 2019
square gridColoringcombinatorics

Problem Statement

Let nn be a positive integer. Every square in a n×nn \times n-square grid is either white or black. How many such colourings exist, if every 2×22 \times 2-square consists of exactly two white and two black squares? The squares in the grid are identified as e.g. in a chessboard, so in general colourings obtained from each other by rotation are different.
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