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 A115983 #24 Feb 16 2025 08:33:00
%S A115983 123,1837,6409,7329,8569,8967,9663,13213,14943,16299,17053,17857,
%T A115983 22611,24601,25261,25729,27847,30567,32413,33321,33379,34257,34557,
%U A115983 34723,38097,39387,39787,39889,39973,43501,43719,44889,48139,49587,53683
%N A115983 Apocalypse primes: 10^665+a(n) has 666 decimal digits and is prime.
%C A115983 This sequence contains about 10^662 terms, the last of which is 10^666-1157.
%H A115983 Robert G. Wilson v, <a href="/A115983/b115983.txt">Table of n, a(n) for n = 1..6666</a>
%H A115983 Brady Haran and Tony Padilla, <a href="https://www.youtube.com/watch?v=KXO2l7Kh60A">Interesting 666-digit Numbers</a>, YouTube Numberphile video, 2024.
%H A115983 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ApocalypseNumber.html">Apocalypse Number</a>
%t A115983 lst={};a=10^665;Do[If[PrimeQ[a+n], Print[n];AppendTo[lst, n]], {n, 8!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Aug 30 2008 *)
%t A115983 Select[Range[55000],IntegerLength[10^665+#]==666&&PrimeQ[10^665+#]&] (* _Harvey P. Dale_, Jul 30 2019 *)
%K A115983 base,dumb,fini,nonn
%O A115983 1,1
%A A115983 _Eric W. Weisstein_, Feb 09 2006