Prove that 4 is not a primitive root modulo n, for $ n \ge 2$
63493
Why 4 is not a primitive root modulo p for any prime p?
20908
How to compute $k$'th roots $\!\bmod n$?
57654
Congruent Modulo $n$: definition
154305
Let $\pi$ denote a prime element in $\mathbb Z[i], \pi \notin \mathbb Z, i \mathbb Z$. Prove that $N(\pi)=2$ or $N(\pi)=p$, $p \equiv 1 \pmod 4$
38805
Prove that $x^{2} \equiv -1 \pmod p$ has no solutions if prime $p \equiv 3 \pmod 4$.
75318
How do you prove that a prime is the sum of two squares iff it is congruent to 1 mod 4?
32136
How to prove Lucas's Converse of Fermat's Little Theorem without using primitive root?
77969
Question about proof for $S_4 \cong V_4 \rtimes S_3$
141184
Proof that a degree 4 polynomial has at least two roots
115241
If $p$ and $q = 2p + 1$ are both odd primes, show that $-4$ and $2(-1)^{(1/2)(p-1)}$ are both primitive roots modulo $q$.
153123
Proving by induction $4^n  0$
95111
Elementary proof for $\sqrt{p_{n+1}} \notin \mathbb{Q}(\sqrt{p_1}, \sqrt{p_2}, \ldots, \sqrt{p_n})$ where $p_i$ are different prime numbers.
44864
Prove, formally that: $\log_2 n! \ge n$ , for all integers $n>3$.
10629
How to prove $4(n!)>2^{n+2}$ for $ n\geq 4$ with induction
2614
Prove that , any primitive root $r$ of $p^n$ is also a primitive root of $p$
52542
For which odd positive integer $n$ , is it true that $-1$ is not a positive power of $2$ modulo $n$?
124240
Inductive proof of $\,9 \mathrel| 4^n+6n-1\,$ for all $\,n\in\Bbb N$