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 A039011 #13 Jun 20 2021 17:30:25 %S A039011 0,2,4,8,10,12,14,16,20,22,24,28,38,40,42,44,48,50,52,54,58,60,62,64, %T A039011 66,70,72,74,76,80,82,84,86,96,100,102,104,108,110,112,114,116,120, %U A039011 122,124,128,138,140,142,144,148,168,178,188,190,192,194,198,200,202 %N A039011 Numbers whose base-5 representation has the same number of 1's and 3's. %H A039011 Daniel Starodubtsev, <a href="/A039011/b039011.txt">Table of n, a(n) for n = 1..10000</a> %Y A039011 Cf. A007091. %K A039011 nonn,base,easy %O A039011 1,2 %A A039011 _Olivier Gérard_