Problems & Puzzles:
n^n = n mod [prime(n)]
Firoozbakht sent the following puzzle:
20201^20201 = 20201 [mod prime(20201)]
b) 20201 is a prime
find more primes with this property (*) ?
J. K. Andersen wrote:
The next prime is 6800832991. There are no others below 10^11