coloring a 2x5 table
Source: 2020 Dürer Math Competition Finals Day2 E12 https://artofproblemsolving.com/community/c1622639_2020_
January 7, 2022
combinatoricsColoring
Problem Statement
We have a white table with rows and columns , and would like to colour all cells of the table according to the following rules: We must colour the cell in the bottom left corner first.
After that, we can only colour a cell if some adjacent cell has already been coloured. (Two cells are adjacent if they share an edge.)How many different orders are there for colouring all squares (following these rules)?