Example 4 Let be a prime. Prove: There exist infinitely many positive integers , such that .
untranslated text remains the same as requested.
Example 4 Let be a prime. Prove: There exist infinitely many positive integers , such that .
untranslated text remains the same as requested.
Prove that if , then taking as an even number, we have , and the proposition holds. Suppose , then by Fermat's Little Theorem, we know
Therefore, for any positive integer , we have
So, it suffices to prove that there are infinitely many positive integers such that
And this only requires , and there are certainly infinitely many such .
Therefore, the proposition holds.