About $n^2+(n+1)^2=z^2$.
100913
It is impossible for $(x-1)^2+x^2+(x+1)^2$ to be a perfect square
100375
Prove that ${\sqrt {n} }^{\sqrt {n+1}} > {\sqrt {n+1}}^{\sqrt {n}}$.
137010
What are integers $x$ and $n$ such as $ x^4+x^3+x^2+x+1 = n^2$?
65000
prove that $x^2 + y^2 = z^4$ has infinitely many solutions with $(x,y,z)=1$
118372
Combination proof for $n(n+1)2^{n-2}=\sum_{k=1}^{n}k^2\binom{n}{k}$
86211
If $x+y+z \geq xyz$ Prove that $x^2 + y^2 + z^2 \geq xyz$.
62254
Show $F_{n+1} \cdot F_{n-1} = F_n^2 + (-1)^n$ for all $n \in \mathbb{N}$
101448
Is $\sin^2(z) + \cos^2(z)=1$ still true for $z \in \Bbb{C}$?
66210
Prove that $z^n + 1/{z^n}$ is a rational number
146126
Infinite positive integer solutions of the equation: $x^2+x+1=(y^2+y+1)(n^2+n+1)$
71756
diophantine equation: $x^2 +y^2 = z^n$
82571
Number of solutions of $x^2=1$ in $\mathbb{Z}/n\mathbb{Z}$
27922
prove that $\binom{n}{0}^2+\binom{n}{1}^2+\binom{n}{2}^2+\cdots+\binom{n}{n}^2=\binom{2n}{n}$
9435
Prove that $1^2+2^2+\cdots+n^2=\frac{n(n+1)(2n+1)}{6}$ for $n \in \mathbb{N}$.
31698
$f(m^2 + f(n)) = f(m)^2 + n$ for all natural numbers
155995
Fibonacci proof question: $f_{n+1}f_{n-1}-f_n^2=(-1)^n$
20705
On equations $m^2+1=5^n$