Modulo division: Find all integers $k \geq 2$ such that $k^2 = 5k(\mod 15).$
124241
Finding all integers $k \geq 2$ such that $k^2 \equiv 5k \pmod{15}$. What is going on here?
91113
$ \exists a, b \in \mathbb{Z} $ such that $ a^2 + b^2 = 5^k $
136300
{5,15,25,35} is a group under multiplication mod 40
105225
Number Theory: Complete set of residues modulo $n$
109490
Modular arithmetic problem (mod $13$)
19459
Find remainder of $F_n$ when divided by $5$
105442
Show that any prime divisor of $x^4+x^3+x^2+x+1$, with $x\in\mathbb{N}$, is $5$ or $1$ mod $5$
63383
Integers $n$ for which $|2^n + 5^n – 65|$ is a perfect square
109532
Proving $5^n \equiv 1 \pmod {2^r}$ when $n=2^{r-2}$
143501
Find all $n\in\mathbb N^+$ such that the sum of the digits of $5^n$ is equal to $2^n$.
134921
Find the number of all subsets of $\{1, 2, \ldots,2015\}$ with $n$ elements such that the sum of the elements in the subset is divisible by 5
87813
How to show that for all k, $k! \ge (k/2)^{k/2}$
107008
Find the remainder when $45!$ is divided by $47$?
156266
Solving $|x-2| + |x-5|=3$
104920
Can we find positive integers $a$ and $k \geq 2$ with $2^n - 1 = a^k$?
62996
A problem regarding the proof of ${p^nk\choose p^n}\equiv k\mod p$, where $p\nmid k$.
117999
Prove by contradiction (not using a calculator) that $\sqrt6 + \sqrt2 < \sqrt{15}$?