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 A039007 #14 Jun 20 2021 16:17:06 %S A039007 2,3,4,5,12,13,14,17,18,19,22,23,24,27,28,29,35,40,45,51,55,62,63,64, %T A039007 67,68,69,72,73,74,76,80,87,88,89,92,93,94,97,98,99,101,105,112,113, %U A039007 114,117,118,119,122,123,124,126,130,137,138,139,142,143,144,147,148 %N A039007 Numbers whose base-5 representation has the same number of 0's and 1's. %H A039007 Daniel Starodubtsev, <a href="/A039007/b039007.txt">Table of n, a(n) for n = 1..10000</a> %t A039007 Select[Range[200],DigitCount[#,5,0]==DigitCount[#,5,1]&] (* _Harvey P. Dale_, May 30 2013 *) %Y A039007 Cf. A007091. %K A039007 nonn,base,easy %O A039007 1,1 %A A039007 _Olivier Gérard_