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 A043626 #13 Apr 25 2021 12:10:27 %S A043626 520,522,523,524,525,526,527,528,529,531,532,533,534,535,536,537,538, %T A043626 540,541,542,543,544,545,546,547,549,550,551,552,553,554,555,556,558, %U A043626 559,560,561,562,563,564,565,567,568,569,570 %N A043626 Numbers whose base-8 representation has exactly 4 runs. %H A043626 Harvey P. Dale, <a href="/A043626/b043626.txt">Table of n, a(n) for n = 1..1000</a> %t A043626 Select[Range[600],Length[Split[IntegerDigits[#,8]]]==4&] (* _Harvey P. Dale_, Jun 18 2019 *) %Y A043626 Cf. A007094. %K A043626 nonn,base %O A043626 1,1 %A A043626 _Clark Kimberling_