MathDB
Divisibility with sum of squares

Source: Spain MO 2023 P3

March 10, 2023
number theory

Problem Statement

Find all quadruples (a,b,c,d)(a,b,c,d) of positive integers satisfying that a2+b2=c2+d2a^2+b^2=c^2+d^2 and such that ac+bdac+bd divides a2+b2a^2+b^2.