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 A043686 #7 Apr 13 2021 23:07:50 %S A043686 1365,2389,2645,2709,2725,2729,2730,2731,2733,2741,2773,2901,3413, %T A043686 4437,4693,4757,4773,4777,4778,4779,4781,4789,4821,4949,5205,5269, %U A043686 5285,5289,5290,5291,5293,5301,5333,5397,5413,5417 %N A043686 a(n) = (1/2)*(n-th number whose base-2 representation has exactly 12 runs). %K A043686 nonn,base %O A043686 1,1 %A A043686 _Clark Kimberling_