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 A043669 #11 Aug 29 2025 16:19:14 %S A043669 15,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,33,34,35,36,37,38,39, %T A043669 40,41,42,43,44,45,46,47,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63, %U A043669 65,66,67,68,69,70,71,72,73,74,75,76,77,78 %N A043669 Numbers whose base-15 representation has exactly 2 runs. %Y A043669 Subsequence of A043704. %K A043669 nonn,base,changed %O A043669 1,1 %A A043669 _Clark Kimberling_