Problem

Source: 2020 1st Memorial Mathematical Contest "Aleksandar Blazhevski-Cane" p3

Tags: number theory



For given integers $n>0$ and $k> 1$, let $F_{n,k}(x,y)=x!+n^k+n+1-y^k$. Prove that there are only finite couples $(a,b)$ of positive integers such that $F_{n,k}(a,b)=0$