Problem

Source: 2020 Dürer Math Competition Finals Day2 E+6 https://artofproblemsolving.com/community/c1622639_2020_

Tags: number theory, divides



Positive integers a,b and c are all less than 2020. We know that a divides b+c, b divides a+c and c divides a+b. How many such ordered triples (a,b,c) are there? Note: In an ordered triple, the order of the numbers matters, so the ordered triple (0,1,2) is not the same as the ordered triple (2,0,1).