Artin’s conjecture on primitive roots
Let be a number in the list or for some . Then we know that has a primitive root![]()
, but finding one can be a rather challenging problem (theoretically and computationally).
Gauss conjectured that the number is a primitive root for infinitely many primes . Much later, in , Emil Artin made the following conjecture:
Artin’s Conjecture.
Let be an integer not equal to or a square. Then is a primitive root for infinitely many primes .
However, up to now, nobody has been able to show that a single integer is a primitive root for infinitely many primes. It can be shown that the number is a primitive root for every Fermat prime![]()
but, unfortunately, the existence of infinitely many Fermat primes is far from obvious, and in fact it is quite dubious (only five Fermat primes are known!).