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 A135585 #19 Oct 20 2016 12:55:07
%S A135585 0,0,0,0,0,0,0,1,1,1,1,2,2,3,4,5,5,5,5,6,6,7,8,9,9,10,11,12,13,14,15,
%T A135585 16,16,16,16,17,17,18,19,20,20,21,22,23,24,25,26,27,27,28,29,30,31,32,
%U A135585 33,34,35,36,37,38,39,40,41,41,41,41,41,42
%N A135585 a(n) = Sum_{i=1..n} (floor(S2(i)/3) mod 2), where S2(i) = A000120(i).
%C A135585 Sequence A115384 is a(n) = Sum_{i=1..n} (floor(S2(n)*1/1) mod 2) = Sum_{i=1..n} (S2(n) mod 2).
%H A135585 G. C. Greubel, <a href="/A135585/b135585.txt">Table of n, a(n) for n = 0..1000</a>
%p A135585 A000120 := proc(n) local i ; add(i,i=convert(n,base,2)) : end: A135585 := proc(n) add(floor(A000120(i)/3) mod 2,i=1..n) ; end: seq(A135585(n),n=0..80) ; # _R. J. Mathar_, Apr 22 2008
%t A135585 f[n_] := n - Sum[Floor[n/2^k], {k, 1, Infinity}]; Table[Sum[Mod[Floor[f[i]/3], 2], {i,1,n}], {n,0,25}] (* _G. C. Greubel_, Oct 20 2016 *)
%o A135585 (PARI) a(n) = sum(i=1, n, hammingweight(i)\3 % 2); \\ _Michel Marcus_, Sep 19 2015
%Y A135585 Cf. A115384, A010060.
%K A135585 easy,nonn,base
%O A135585 0,12
%A A135585 _Ctibor O. Zizka_, Feb 25 2008
%E A135585 Definition corrected by _R. J. Mathar_, Apr 22 2008