CZ-SK-MO 2020 Problem 4

Positive integers $a, b$ satisfy equality $b^2 = a^2 + ab + b$ . Prove that $b$ is a square of a positive integer.

(Patrik Bak)

Dataset text AI-MO AoPS. Quoted with source.

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.