MathDB
a^2 + b^2 =p^2-q^2 2009 Romania District VII p3

Source:

August 16, 2024
number theoryPerfect Squares

Problem Statement

Let aa and bb be non-negative integers. Prove that the number a2+b2a^2 + b^2 is the difference of two perfect squares if and only if abab is even.