### $x^y = y^x$ for integers $x$ and $y$

#### Posted by **Paulo Argolo**, at **math.stackexchange.com**,

We know that $2^4 = 4^2$ and $(-2)^{-4} = (-4)^{-2}$. Is there another pair of integers $x, y$ ($x\neq y$) which satisfies the…