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 A031184 #13 Feb 16 2025 08:32:35 %S A031184 66,127,172,217,228,271,282,445,454,456,465,544,546,564,606,645,654, %T A031184 660,712,721,822,1027,1072,1137,1149,1173,1188,1194,1207,1248,1270, %U A031184 1277,1278,1284,1287,1317,1369,1371,1396,1419,1428,1456,1465,1482 %N A031184 Numbers having period-2 4-digitized sequences. %H A031184 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Digitaddition.html">Digitaddition</a> %K A031184 nonn,base %O A031184 1,1 %A A031184 _Eric W. Weisstein_