MathDB
smallest no of 3-cell to point a 5x5 square, painting at most 1 corner

Source: Caucasus 2015 10.3

April 26, 2019
combinatoricscombinatorial geometryTilingtiles

Problem Statement

What is the smallest number of 33-cell corners that you need to paint in a 5×55 \times5 square so that you cannot paint more than one corner of one it? (Shaded corners should not overlap.)