IMO ShortList 2002, combinatorics problem 2
Source: IMO ShortList 2002, combinatorics problem 2
September 28, 2004
combinatoricsTilingdissectionIMO Shortlist
Problem Statement
For an odd positive integer, the unit squares of an chessboard are coloured alternately black and white, with the four corners coloured black. A it tromino is an -shape formed by three connected unit squares. For which values of is it possible to cover all the black squares with non-overlapping trominos? When it is possible, what is the minimum number of trominos needed?