MathDB
$x^2+y^2+z^2-xy-yz-zx=3$

Source: Serbia JBMO TST 2012

October 6, 2023

Problem Statement

Show that the equation x2+y2+z2xyyzzx=3x^2+y^2+z^2-xy-yz-zx=3 has an infinity solutions over nonnegative integers.