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 A043707 #8 Jun 18 2021 23:04:19 %S A043707 1,2,3,5,10,15,17,18,19,21,24,25,27,28,29,30,33,34,35,36,38,39,42,44, %T A043707 45,46,49,50,51,52,54,55,56,57,59,63,65,66,67,69,74,79,81,82,83,85,88, %U A043707 89,91,92,93,94,96,101,104,105,107,111,112,117 %N A043707 Numbers whose base-4 representation has an odd number of runs. %K A043707 nonn,base %O A043707 1,2 %A A043707 _Clark Kimberling_