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 A344345 #7 May 16 2021 02:41:05
%S A344345 3,8,12,14,33,35,39,47,49,51,55,57,59,61,130,132,134,136,140,142,144,
%T A344345 152,156,158,160,176,184,188,190,194,196,198,200,204,206,208,216,220,
%U A344345 222,226,228,230,232,236,238,242,244,246,250,517,521,523,525,529,531,535
%N A344345 Digitally balanced numbers in Gray code: numbers whose binary reflected Gray code has the same number of 0's as 1's.
%H A344345 Amiram Eldar, <a href="/A344345/b344345.txt">Table of n, a(n) for n = 1..10000</a>
%H A344345 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GrayCode.html">Gray Code</a>.
%H A344345 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gray_code">Gray code</a>.
%e A344345 8 is a term since its Gray code, 1100, has 2 0's and 2 1's.
%e A344345 33 is a term since its Gray code, 110001, has 3 0's and 3 1's.
%t A344345 gc[n_] := gc[n] = If[n <= 1, n, 2^(b = Floor@Log2[n]) + gc[2^(b + 1) - 1 - n]]; gcDigBalQ[n_] := Equal @@ DigitCount[gc[n], 2, {0, 1}]; Select[Range[500], gcDigBalQ]
%Y A344345 Cf. A005811, A014550.
%Y A344345 Similar sequences: A031443 (binary), A210619 (Zeckendorf), A342727 (base i-1).
%K A344345 nonn,base
%O A344345 1,1
%A A344345 _Amiram Eldar_, May 15 2021