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 A186538 #26 Apr 03 2023 10:36:12 %S A186538 25,26,28,33,49,80,81,133,179,202,222,271,411,588,682,1039,2403,5802, %T A186538 11544,12484,41047,46396 %N A186538 Numbers n>0 such that 666*10^n+7 is prime. %C A186538 Some of the larger entries may only correspond to probable primes. %H A186538 Chris Caldwell, The Prime Glossary, <a href="https://t5k.org/glossary/xpage/BeastlyPrime.html">Beastly prime</a> %H A186538 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/16957.html">Prime Curios! 66600...00007 (28-digits)</a> %H A186538 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=666*10^n%2B7&action=Search">PRP Records</a> %H A186538 R. Ondrejka, <a href="http://www.utm.edu/research/primes/lists/top_ten/">The Top Ten: a Catalogue of Primal Configurations</a> %t A186538 Select[Range[10^3], PrimeQ[666*10^# + 7] &] (* _Arkadiusz Wesolowski_, Sep 08 2011 *) %Y A186538 Cf. A186086. %K A186538 nonn,base,more %O A186538 1,1 %A A186538 _Arkadiusz Wesolowski_, Feb 23 2011 %E A186538 a(21) from _Arkadiusz Wesolowski_, May 25 2011 %E A186538 a(22) from _Arkadiusz Wesolowski_, May 28 2011