Sum of square $i^2+j^2 = x^2+1$ with $\gcd(i, j) = 1$
18203
Diophantine equation $a^2+b^2=c^2+d^2$
67899
Integer squares of the form $x^4+x^3+x^2+x+1$
25573
If $\gcd(a,b)=1$, then $\gcd(a+b,a^2 -ab+b^2)=1$ or $3$.
113641
Suppose the gcd (a,b) = 1 and c divides a + b. Prove that gcd (a,c) = 1 = gcd (b,c)
129605
$ 2g(z)=g(\frac{z}{2}) + g(\frac{z+1}{2})$
67666
show that $a^2+b^2+c^2+2abc+3\ge (1+a)(1+b)(1+c)$
91506
If $\gcd(a,b) = 1$ then $\gcd(a,a + b) = 1$
4194
Which integers can be expressed as a sum of squares of two coprime integers?
19500
How can I find $\gcd(a^m+1,a^n+1)$ with $a,m,n$ positive integers?
15168
If $a,b$ are positive integers such that $\gcd(a,b)=1$, then show that $\gcd(a+b, a-b)=1$ or $2$. and $\gcd(a^2+b^2, a^2-b^2)=1$ or $2 $
53777
Why is $\gcd(x^4+1,x^2-1) = 1$ but I get $2$? [unit normalization of gcds]
114414
Sum of $\sum_{k=1}^n\sin{k\theta}$
110996
Sum of the form $r+r^2+r^4+\dots+r^{2^k} = \sum_{i=1}^k r^{2^i}$
72437
Sum of the digits of a perfect square
59006
Proof of $\gcd(n!+1, (n+1)!+1)=1$?
135086
GCD of two numbers divided by their greatest common divisor is 1
60842
if $a^2+b^2=c^2$ then $gcd(a,b)=gcd(a,c)=gcd(b,c)$.