Which of these integers can be written as the sum of two squares of integers?
1001
Number of integer solutions of $x^2 + y^2 = k$
131731
Primes that can't be written as sum of two squares. Mod
153769
Numbers that can be expressed as the sum of two cubes in exactly two different ways
76370
Can any integer can be written as the sum of 8 integer cubes?
18633
Prove every odd integer is the difference of two squares
94570
Proof that every odd integer is a difference of two squares
67899
Integer squares of the form $x^4+x^3+x^2+x+1$
67332
Sum of two squares modulo p
144779
The number of ways to represent $(n^2+n)/4$ as a sum of $n/2$ distinct integers in $1,\dots,n$
11506
Alternative proof that $(a^2+b^2)/(ab+1)$ is a square when it's an integer
46606
Can an integer of the form $4n+3$ written as a sum of two squares?
132125
finding if two binary quadratic forms represent the same integers
69194
Partitioning sum of squares
72389
Positive integer $n$ such that $2n+1$ , $3n+1$ are both perfect squares
41789
Fermat's theorem on sums of two squares
119046
Expressing a positive integer as a sum of positive integers
40080
Sum of multiples of $2$ coprime numbers cover positive integers