Dividing a square into (n-1)^2 congruent squares
Source: IMO LongList 1970 - P53
May 22, 2011
conicsparabolaanalytic geometryarithmetic sequencecombinatorics unsolvedcombinatorics
Problem Statement
A square is divided into congruent squares, with sides parallel to the sides of the given square. Consider the grid of all corners obtained in this manner. Determine all integers for which it is possible to construct a non-degenerate parabola with its axis parallel to one side of the square and that passes through exactly points of the grid.