Prove that the square of a prime of form $4k+1$ is the sum of two squares
62747
Use induction to prove a product of sums of squares is a sum of squares
114863
Representing a given number as the sum of two squares.
41789
Fermat's theorem on sums of two squares
146512
Prove that for every prime number $p>3$, $4p^2+1$ can be written as the sum of three square numbers
34692
Prove if $ p$ is a prime of the form $3n+1$, then $p$ is also of the form $6m+1$
158161
$\mathbb{Q}(\sqrt p_{1}+\sqrt p_{2})=\mathbb{Q}(\sqrt p_{1},\sqrt p_{2})$ for $p_{1},p_{2}$ primes.
135458
When is a sum of consecutive squares equal to a square?
1837
Showing that $1^k+2^k + \dots + n^k$ is divisible by $n(n+1)\over 2$
143540
How to prove this decomposition of sum of squares?
5841
Proving prime $p$ divides $\binom{p}{k}$ for $k\in\{1,\ldots,p-1\}$
58264
How to derive the formula for the sum of the first $n$ perfect squares?
57275
On the primality of integers of the form $p^2+k$
138081
How to determine whether a number can be written as a sum of two squares?
146241
If $a \in \Bbb Z$ is the sum of two squares then $a$ can't be written in which of the following forms?
70066
Show that product of primes, $\prod_{k=1}^{\pi(n)} p_k < 4^n$
66216
Squares, Cubes and Prime numbers
33735
The square of an integer is congruent to 0 or 1 mod 4