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 A019346 #18 Jan 31 2018 12:34:58 %S A019346 2,7,11,13,23,29,37,41,43,47,53,83,89,113,139,163,173,191,193,239,251, %T A019346 257,263,269,281,293,311,317,337,347,359,367,401,419,433,443,449,463, %U A019346 467,479,491,499,503,509,521,569,571,587,601,619,631,641,643,647,673,677,719 %N A019346 Primes with primitive root 19. %H A019346 Vincenzo Librandi, <a href="/A019346/b019346.txt">Table of n, a(n) for n = 1..1000</a> %H A019346 <a href="/index/Pri#primes_root">Index entries for primes by primitive root</a> %t A019346 Select[Prime[Range[200]], MultiplicativeOrder[19, #] == # - 1 &] %K A019346 nonn,easy %O A019346 1,1 %A A019346 _David W. Wilson_