Moving pairs of knights
Source: Mexico National Olympiad 2017, Problem 1
November 6, 2017
combinatoricsboardknight
Problem Statement
A knight is placed on each square of the first column of a board. A move consists in choosing two different knights and moving each of them to a square which is one knight-step away. Find all integers with such that it is possible for each square in the -th column to contain one knight after a finite number of moves.Note: Two squares are a knight-step away if they are opposite corners of a or board.