>>13140556Watched this film the other night, called X + Y, about the maths olympiad. One of the problems they had in practise was:
Prove/disprove that there are an infinite number of integers mn, where m divides n^2 + 1 and n divides m^2 + 1.
Where do you start? I assumed it was by showing that mn = ((n^2 +1)/j) ((m^2 +1)/k)
for integers j and k, but where do you go from
(nm)^2 + m^2 + n^2 + 1 / jk ?
