Quote:
Originally Posted by devarajkandadai
There seems to be no nonresidues higher than quadratic order;is this related to Fermat's last theorem?

Sorry;just proved that 23 is a nonresidue of 7919 upto infinite order. This was done with aid of my paper "Euler's generalization of Fermat's theorem ( a further generalization) Hawaii international conference ,2004.
Verification : pari code 
Is=Mod(17,7919)^7922 = =23