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 A039337 #18 Nov 25 2021 07:32:19
%S A039337 11,25,67,83,88,90,92,93,94,95,99,107,115,123,139,153,193,200,202,204,
%T A039337 205,206,207,209,225,233,241,249,267,281,331,345,395,409,459,473,515,
%U A039337 531,536,538,540,541,542,543,547,555,563,571,603,643,659,664,666,668
%N A039337 Numbers whose base-8 representation has the same nonzero number of 1's and 3's.
%H A039337 Michael S. Branicky, <a href="/A039337/b039337.txt">Table of n, a(n) for n = 1..10000</a>
%t A039337 Select[Range[700],DigitCount[#,8,1]==DigitCount[#,8,3]>0&] (* _Harvey P. Dale_, Oct 24 2015 *)
%o A039337 (Python)
%o A039337 def ok(n): o = oct(n); return o.count('1') == o.count('3') > 0
%o A039337 print([k for k in range(669) if ok(k)]) # _Michael S. Branicky_, Nov 25 2021
%Y A039337 Cf. A007094.
%K A039337 nonn,base,easy
%O A039337 1,1
%A A039337 _Olivier Gérard_