Is it an open problem? (Sums of squares)
134765
Is an integer a sum of two rational squares iff it is a sum of two integer squares?
67899
Integer squares of the form $x^4+x^3+x^2+x+1$
18932
Squares in arithmetic progression
34617
Number Theory: which primes are a sum of two squares?
142978
combinatorics: sum of product of integer compositions
58264
How to derive the formula for the sum of the first $n$ perfect squares?
92106
Prove that $n$ is a sum of two squares?
46606
Can an integer of the form $4n+3$ written as a sum of two squares?
129755
Weighted sum of squares, in a finite field
150281
Am I on the right track to figure out this combinatorics problem?
21443
The locker problem - why squares?
22800
Can $\sqrt{n} + \sqrt{m}$ be rational if neither $n,m$ are perfect squares?
22973
Show that an integer of the form $8k + 7$ cannot be written as the sum of three squares.
131731
Primes that can't be written as sum of two squares. Mod
149481
Number theory counting sums of squares modulus
98440
Show that any non-negative rational integer may be written as the sum of two squares if it is of the form....
136582
Decomposing total sum of squares