Diophantine equations, factoring, modular arithmatic.
101708
Integers can be expressed as $a^3+b^3+c^3-3abc$
150528
Pythagorean triples $(a,b,c)$ and divisibility of $a$ or $b$ by $3$.
380
Bijection from modular multiplication?
42754
Modular arithmetic: division, fractions, solving linear congruences
56803
Finding solutions to congruence equations
52530
There exists a prime congruent to $m$ mod $p$
360
Modular exponentiation by hand ($a^b\bmod c$)
35504
The Diophantine equation $x^2 + 2 = y^3$
80875
Congruence equation ...
21108
Perfect squares and modularly congruency in mod 5
123159
Solutions of the diophantine equation $x+y+z=xyz$?
36611
Algorithms for solving the discrete logarithm $a^x \equiv b\pmod{n}$ when $\gcd(a,n) \neq 1$
36713
Solving multiple congruences by CRT = Chinese Remainder Theorem
102204
Factoring product of two primes from solutions of congruence
99739
The diophantine equation $x^2+y^2=3z^2$
48657
Solving factorial equations
53157
Factoring Quadratics