How to find the greatest prime number that is smaller than $x$?
64883
What is the most efficient algorithm to find the closest prime less than a given number $n$
27069
sum of all positive integers less than $n$ and relatively prime to $n$
59207
How to create the most compact mapping n → isprime(n) up to a limit N?
112359
How to deal with a Pell's equation type problem with two primes
79208
Is the number $-1$ prime?
107037
How to find prime numbers between 0 - 100?
63356
Can $x^{n}-1$ be prime if $x$ is not a power of $2$ and $n$ is odd?
137875
Are all prime numbers greater than 2 odd?
62061
Do we have negative prime numbers?
127426
Greatest number in the sequence
44857
Why the $(n+1)$th prime number cannot exceed the smallest prime divisor of $p_1\dotsc p_n + 1$
112599
What is the smallest value of n such that an algorithm running at 100*n^2 operates faster than 2^n ? [How to figure out without brute force]
136918
How to determine the smallest numbers with $n$ factors
152008
Least prime of the form $38^n+31$
101882
Does this polynomial evaluate to prime number whenever $x$ is a natural number?
83643
Are there prime gaps of every size?
136856
Diophantine equation with a prime number