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 A048410 #7 Oct 10 2019 23:17:37
%S A048410 0,1,2,3,4,5,6,7,8,9,19,80,91,191,808,919,1919,8080,9191,19191,80808,
%T A048410 91919,191919,808080,919191,1919191,8080808,9191919,19191919,80808080,
%U A048410 91919191,191919191,808080808,919191919,1919191919,8080808080
%N A048410 Numbers whose consecutive digits differ by 8.
%t A048410 With[{nn=10},Join[Range[0,9],Table[FromDigits[PadRight[{},n,{1,9}]],{n,nn}], Table[FromDigits[PadRight[{},m,{9,1}]],{m,nn}],Table[ FromDigits[ PadRight[ {},k,{8,0}]],{k,nn}]]]//Union (* _Harvey P. Dale_, Jul 17 2017 *)
%Y A048410 Cf. A033075, A033088, A033081, A048407-A048409.
%K A048410 nonn,base
%O A048410 0,3
%A A048410 _Patrick De Geest_, Apr 15 1999