If $n\in \Bbb N$ is a primitive root then how to prove that:
There are exactly $\phi(\phi(n))$ primitive roots modulo $n$ such that are peer to peer $\not \equiv$
If $n\in \Bbb N$ is a primitive root then how to prove that:
There are exactly $\phi(\phi(n))$ primitive roots modulo $n$ such that are peer to peer $\not \equiv$