%I #9 Mar 31 2024 15:07:33
%S 2,3,13,29,31,37,41,53,59,67,71,79,89,103,107,113,167,173,179,193,223,
%T 227,257,269,281,293,317,331,337,379,383,401,431,433,439,449,509,521,
%U 547,563,569,601,607,641,659,673,677,683,743,751,773,787,797,827,829,839,857,863
%N Primes for which -19 is a primitive root.
%H Vincenzo Librandi, <a href="/A105891/b105891.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Pri#primes_root">Index entries for primes by primitive root</a>
%t pr=-19; Select[Prime[Range[200]], MultiplicativeOrder[pr, # ] == #-1 &]
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Apr 24 2005