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 A057187 #28 Aug 20 2021 10:02:39 %S A057187 3,5,7,13,37,347,17597,59183,80761,210599,394579 %N A057187 Numbers n such that (21^n+1)/22 is a prime. %C A057187 Some of the larger terms correspond to probable primes. %H A057187 H. Dubner and T. Granlund, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/DUBNER/dubner.html">Primes of the Form (b^n+1)/(b+1)</a>, J. Integer Sequences, 3 (2000), #P00.2.7. %H A057187 H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a> %H A057187 Paul Bourdelais, <a href="https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;417ab0d6.0906">A Generalized Repunit Conjecture</a> [From _Paul Bourdelais_, Mar 24 2010] %o A057187 (Prime95) PRP=1,21,394579,1,0,0,"22" %K A057187 nonn %O A057187 1,1 %A A057187 _N. J. A. Sloane_, Sep 15 2000 %E A057187 a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008 %E A057187 a(8) corresponds to a probable prime discovered by _Paul Bourdelais_, Mar 22 2010 %E A057187 a(9) corresponds to a probable prime discovered by _Paul Bourdelais_, Mar 24 2010 %E A057187 a(10) corresponds to a probable prime discovered by _Paul Bourdelais_, Aug 30 2013 %E A057187 a(11) corresponds to a probable prime discovered by _Paul Bourdelais_, Oct 23 2018