Compute $((p\!-\!1)/2)!\pmod{\!p},\ p = 257,\,$ by Wilson, etc
38285
What is $(65!)^2$ congruent to mod $131$?
29640
If $x \equiv 1 \pmod 3$ and $x \equiv 0 \pmod 2$, what is $x \pmod 6$?
18767
How do you find the modular inverse of $5\pmod{\!11}$
114737
Sum of reciprocals of primes factorial: $\sum_{p\;\text{prime}}\frac{1}{p!}$
84879
Solving infinite sums with primes.
147600
Calculating large Bell number modulo a composite number
27850
Find and prove a formula for $1\pmod{3}\cap 1\pmod{7}$.
144836
How to prove that $\frac{(mn)!}{m!(n!)^m}$ is an integer?
107924
Prove (or derive) the de Polignac formula for the prime decomposition of $n!$
154933
Prove $(p-k)!(k-1)!\equiv (-1)^k \text{ mod p }$
115758
Remainder of division when $p$ is not prime
151764
modular arithmetic, solving $ax + b \equiv c \pmod d$?
157766
Are primes (ignoring $2$) equally likely to be $1~\text{or}~3\pmod 4$?
41614
Formula for prime counting function
37093
If p is an odd prime, prove that $1^2 \times 3^2 \times 5^2 \cdots  \times (p-2)^2 \equiv (-1)^{(p+1)/2}\pmod{p}$
36361
How to calculate the summation $(\sum_{p = k}^{n} \binom{n}{p}) / 2^n$ quickly?
34588
Number Theory: $p!+p=n^2$, $p$ = prime