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 A043696 #10 Jun 18 2021 20:45:05 %S A043696 7,9,10,11,12,13,14,15,17,18,19,20,21,22,23,25,26,27,28,29,30,31,33, %T A043696 34,35,36,37,38,39,41,42,43,44,45,46,47,49,56,58,59,60,61,62,65,73,81, %U A043696 89,97,98,106,112,113,115,116,117,118,122,130 %N A043696 Numbers whose base-7 representation has an even number of runs. %t A043696 Select[Range[200],EvenQ[Length[Split[IntegerDigits[#,7]]]]&] (* _Harvey P. Dale_, Nov 17 2013 *) %K A043696 nonn,base %O A043696 1,1 %A A043696 _Clark Kimberling_