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 A080584 #7 Jun 01 2012 16:05:52
%S A080584 0,0,0,1,1,1,0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,
%T A080584 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,
%U A080584 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%N A080584 A run of 3*2^n 0's followed by a run of 3*2^n 1's, for n=0, 1, 2, ...
%F A080584 a(n) = (1 - (-1)^A079944(A002264(n)) )/2, A079944(A002264(n))=floor(log[2](4*(floor((n+6)/3))/3)) - floor(log[2](floor((n+6)/3))) - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 24 2003
%F A080584 Also a(n) = A079944(A002264(n)) = floor(log[2](4*(floor((n+6)/3))/3)) - floor(log[2](floor((n+6)/3))) - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 24 2003
%p A080584 f := (c,n)->seq(c,i = 1..3*2^n); [f(0,0),f(1,0),f(0,1),f(1,1),f(0,2),f(1,2),f(0,3),f(1,3)]; f;
%t A080584 Flatten[Table[{PadRight[{},3*2^n,0],PadRight[{},3*2^n,1]},{n,0,4}]] (* _Harvey P. Dale_, Jun 01 2012 *)
%Y A080584 Equals A080586 - 1.
%K A080584 nonn
%O A080584 0,1
%A A080584 _N. J. A. Sloane_, Feb 23 2003