Quote:
Originally Posted by devarajkandadai
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

This example is not correct.correct example:
23 is nonresidue of 3571 upto infinite order.I leave it to pari experts like Charles to verify.