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 A043712 #10 Jun 18 2021 23:07:20 %S A043712 1,2,3,4,5,6,7,8,10,20,30,40,50,60,70,80,82,83,84,85,86,87,88,89,91, %T A043712 99,100,102,103,104,105,106,107,108,109,110,112,113,114,115,116,117, %U A043712 118,119,120,122,123,124,125,126,127,128,129,130 %N A043712 Numbers whose base-9 representation has an odd number of runs. %t A043712 Select[Range[200],OddQ[Length[Split[IntegerDigits[#,9]]]]&] (* _Harvey P. Dale_, Nov 08 2012 *) %K A043712 nonn,base %O A043712 1,2 %A A043712 _Clark Kimberling_