How to prove that $g$ or $g+p$ is a primitive root modulo $p^a$ for a primitive root $g$ modulo $p$?
Posted by Joakim G, at math.stackexchange.com,
I wish to prove the following: If $p$ is an odd prime and $g$ is a primitive root modulo $p$, then either $g$ or $g+p$ is a…