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 A043705 #10 Jun 18 2021 23:03:47 %S A043705 16,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,35,36,37,38,39,40, %T A043705 41,42,43,44,45,46,47,48,49,50,52,53,54,55,56,57,58,59,60,61,62,63,64, %U A043705 65,66,67,69,70,71,72,73,74,75,76,77,78,79 %N A043705 Numbers whose base-16 representation has an even number of runs. %o A043705 (Python) %o A043705 from itertools import groupby %o A043705 def ok(n): return len(list(g for k, g in groupby(hex(n)[2:])))%2 == 0 %o A043705 print(list(filter(ok, range(1, 80)))) # _Michael S. Branicky_, Jun 18 2021 %K A043705 nonn,base %O A043705 1,1 %A A043705 _Clark Kimberling_