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Tri-connected squares

Source: APMO 2018 P3

June 24, 2018
combinatoricsAPMO

Problem Statement

A collection of nn squares on the plane is called tri-connected if the following criteria are satisfied:
(i) All the squares are congruent. (ii) If two squares have a point PP in common, then PP is a vertex of each of the squares. (iii) Each square touches exactly three other squares.
How many positive integers nn are there with 2018n30182018\leq n \leq 3018, such that there exists a collection of nn squares that is tri-connected?