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 A019357 #17 Jan 31 2018 11:41:05 %S A019357 2,7,17,29,47,53,59,61,67,71,73,89,107,131,137,197,227,229,241,269, %T A019357 277,283,307,311,313,337,353,359,379,389,401,419,431,433,439,443,449, %U A019357 457,461,467,479,503,509,557,563,569,599,607,673,677,683,709,727,751,757,761,773 %N A019357 Primes with primitive root 31. %H A019357 Vincenzo Librandi, <a href="/A019357/b019357.txt">Table of n, a(n) for n = 1..1000</a> %H A019357 <a href="/index/Pri#primes_root">Index entries for primes by primitive root</a> %t A019357 Select[Prime[Range[200]], MultiplicativeOrder[31, # ] == # - 1 &] %K A019357 nonn,easy %O A019357 1,1 %A A019357 _David W. Wilson_