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 A165406 #3 Mar 31 2012 13:21:19 %S A165406 0,1,100,110,111,10000,10010,10011,11000,11001,11100,11110,11111, %T A165406 1000000,1000010,1000011,1001000,1001001,1001100,1001110,1001111, %U A165406 1100000,1100001,1100100,1100110,1100111,1110000,1110010,1110011 %N A165406 Sequence A165404 shown in binary, or equivalently, sequence A163901 in quaternary base. %H A165406 A. Karttunen, <a href="/A165406/b165406.txt">Table of n, a(n) for n = 0..609</a> %Y A165406 a(n) = A007088(A165404(n)) = A007090(A163901(n)). For n>0, A147600(n-1) seems to give the number of terms with n binary digits. %K A165406 nonn,base %O A165406 0,3 %A A165406 _Antti Karttunen_, Sep 19 2009