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 A043617 #13 Aug 29 2025 16:13:08 %S A043617 7,9,10,11,12,13,14,15,17,18,19,20,21,22,23,25,26,27,28,29,30,31,33, %T A043617 34,35,36,37,38,39,41,42,43,44,45,46,47,49,56,58,59,60,61,62,65,73,81, %U A043617 89,97,98,106,112,113,115,116,117,118,122,130 %N A043617 Numbers whose base-7 representation has exactly 2 runs. %Y A043617 Cf. A007093. %Y A043617 Subsequence of A043696. %K A043617 nonn,base,changed %O A043617 1,1 %A A043617 _Clark Kimberling_