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 A048406 #5 Oct 10 2019 23:18:37 %S A048406 0,1,2,3,4,5,6,7,8,9,15,26,37,40,48,51,59,62,73,84,95,151,159,262,373, %T A048406 404,484,515,595,626,737,840,848,951,959,1515,1595,2626,3737,4040, %U A048406 4048,4840,4848,5151,5159,5951,5959,6262,7373,8404,8484,9515,9595,15151 %N A048406 Numbers whose consecutive digits differ by 4. %Y A048406 Cf. A033075, A033088, A033081, A048407-A048410. %K A048406 nonn,base %O A048406 0,3 %A A048406 _Patrick De Geest_, Apr 15 1999