Can somebody help me with this. I am trying to prove something from Fermat's equation.
Fermat's Equation $x^n + y^n = z^n$, where $x,y,z$ and $n$ are positive integers. His last theorem states that this equation has no solution if $n \geq3$. I want to prove that if the equation has no solution if $n$ is prime or $n = 4$, then it must be true that it has no solution if $n \geq3$.