Why must $n$ be even if $2^n+1$ is prime?
2802
If $2^n+1$ is prime, why must $n$ be a power of $2$?
23544
Complete induction proof that every $n > 1$ can be written as a product of primes
158563
If $m^4+4^n$ is prime, then $m=n=1$ or $m$ is odd and $n$ even
34588
Number Theory: $p!+p=n^2$, $p$ = prime
76807
How come if $\ i\ $ not of the following form, then $12i + 5$ must be prime?
35553
If $n$ is composite, so is $2^n-1$
38748
There are infinitely many prime numbers $p$ for which $p + 2$ and $p + 4$ are also prime numbers
137875
Are all prime numbers greater than 2 odd?
43939
Show that $3^{2n+1}-4^{n+1}+6^n$ is never prime for natural n except 1.
2218
Prove that $(n-1)! \equiv -1 \pmod{n}$ iff $n$ is prime [Wilson's Theorem]
107502
Let $p \geq 2$. Prove that if $2^p-1$ is prime then $p$ must also be prime.
68068
For any integer n greater than 1, $4^n+n^4$ is never a prime number.
8710
Bounds for $n$-th prime
81250
Infinitude of prime numbers
132132
Are there infinitely many primes of the form $6^{2n}+1$ or only finitely many?
39915
Let $n$ be an integer such that if $d | n$ then $d + 1 | n + 1.$ Show that $n$ is a prime number
24572
Does $n \mid 2^{2^n+1}+1$ imply $n \mid 2^{2^{2^n+1}+1}+1$?