This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A019367 #17 Nov 15 2014 09:19:38
%S A019367 5,23,31,37,59,71,73,83,101,109,137,163,173,191,223,227,233,239,241,
%T A019367 251,263,269,271,281,293,331,359,367,373,379,401,409,419,431,449,461,
%U A019367 467,499,509,563,569,587,599,601,613,617,677,727,739,757,769,773,797,809,863,877
%N A019367 Primes with primitive root 42.
%H A019367 Vincenzo Librandi, <a href="/A019367/b019367.txt">Table of n, a(n) for n = 1..1000</a>
%H A019367 <a href="/index/Pri#primes_root">Index entries for primes by primitive root</a>
%t A019367 pr=42; Select[Prime[Range[200]], MultiplicativeOrder[pr, # ] == #-1 &]
%t A019367 Join[{5,23,31,37},Select[Prime[Range[200]],MemberQ[ PrimitiveRootList[ #],42]&]] (* _Harvey P. Dale_, Nov 15 2014 *)
%K A019367 nonn
%O A019367 1,1
%A A019367 _David W. Wilson_