The congruence is clearly true for Suppose is odd. We have
as is odd. Therefore
and you can easily complete the proof from here.
Hi ... I'm going through the Zhao and Sun proof of "Some Curious Congruences Modulo Primes", and I'm stuck in several places, hehehe. In particular, I was wondering how the following congruence was shown.
I get the equality part, no problem. But it's not so clear (for me) how the congruence can be shown. Any help would be great ... I'm learning quite a bit