Question 70
Find all prime numbers $a$, $b$, $c$ and positive integers $k$ satisfying the equation
$$
a^2 + b^2 + 16c^2 = 9k^2 + 1
$$
$$
a^2 + b^2 + 16c^2 = 9k^2 + 1
$$
MathNet 2015-part-04 — 191 problems (EN–VI) Question 70
Math Olympiad Vault · MathNet 2015-part-04 — 191 problems (EN–VI)