How do we identify if a number can be represented as the sum of squares of$ 3$ integers?
131625
Expressing an integer as the sum of three squares
124667
Let $S=\{3,4,5,6,7,8,9,10,11,12\}$. Suppose 6 integers are chosen from S. Must there be 2 integers whose sum is 15?
146241
If $a \in \Bbb Z$ is the sum of two squares then $a$ can't be written in which of the following forms?
144779
The number of ways to represent $(n^2+n)/4$ as a sum of $n/2$ distinct integers in $1,\dots,n$
113511
What's a good algorithm to determine if an input is a perfect square?
61268
Is there a combinatorial interpretation of the triangular numbers?
46606
Can an integer of the form $4n+3$ written as a sum of two squares?
112644
The product of two numbers that can be written as the sum of two squares
16472
Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
140359
Can the sum of finitely many inverses of distinct odd integers $\geq 3$ be 1?
131731
Primes that can't be written as sum of two squares. Mod
131108
Can $3p^4-3p^2+1$ be square number?
129755
Weighted sum of squares, in a finite field
18932
Squares in arithmetic progression
72389
Positive integer $n$ such that $2n+1$ , $3n+1$ are both perfect squares
23830
Proof that if $p\equiv3\,\left(\mbox{mod 4}\right)$ then $p$ can't be written as a sum of two squares
50615
Expressing a Non Negative Integer as Sums of Two Squares