Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
When $n>3$, $n$ must be $\equiv 0, 2 \pmod 6$
$3$, $7$, $43$, $73$, $157$, $211$, and $421$ are primes,
but $343=7^3$ ($n=18$) is not.
Are there infinitely many primes of the form $n^2+n+1$ ?
Required, but never shown
10 months ago