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 A051003 #24 Feb 16 2025 08:32:41 %S A051003 666,1666,2666,3666,4666,5666,6660,6661,6662,6663,6664,6665,6666,6667, %T A051003 6668,6669,7666,8666,9666,10666,11666,12666,13666,14666,15666,16660, %U A051003 16661,16662,16663,16664,16665,16666,16667,16668,16669,17666,18666 %N A051003 Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion. %H A051003 Jens Kruse Andersen, <a href="/A051003/b051003.txt">Table of n, a(n) for n = 1..1000</a> %H A051003 Tony Padilla and Brady Haran, <a href="https://www.youtube.com/watch?v=zk_Q9y_LNzg">The Most Evil Number</a>, Numberphile video (2018) %H A051003 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BeastNumber.html">Beast Number</a> %t A051003 Select[Range[18666], ! StringFreeQ[ToString[#], "666"] &] (* _Arkadiusz Wesolowski_, Sep 08 2011 *) %Y A051003 Cf. A131645, A057564, A002282, A138563, A043515, A046720, A186086. %K A051003 nonn,less,easy,base %O A051003 1,1 %A A051003 _Eric W. Weisstein_