Let n = k * (p- 1)+r, 0.

The formula 1 is p | (r-k) 2 r- 1.

Fix the value of R and change the value of K to make R-K = 0 ~ P- 1 (mod p) and (R-K) 2 R- 1 different (mod p).

Therefore, (r-I) 2 r- 1 must be a multiple of p.

Then k=Z*p+i corresponds to n=k(p- 1)+r all meet the requirements, obviously there are infinitely many.