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 A031183 #15 Feb 16 2025 08:32:35 %S A031183 0,1,10,12,17,21,46,64,71,100,102,107,120,137,145,154,170,173,201,210, %T A031183 224,242,279,288,297,317,349,357,371,375,379,394,397,406,415,422,439, %U A031183 451,460,493,514,537,541,573,599,604,640,701,710,713,729,731 %N A031183 Numbers having period-1 4-digitized sequences. %H A031183 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Digitaddition.html">Digitaddition</a> %Y A031183 Cf. A031179. %K A031183 nonn,base %O A031183 1,3 %A A031183 _Eric W. Weisstein_ %E A031183 Missing 0 inserted and offset corrected by _Sean A. Irvine_, Apr 14 2020