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 A083055 #9 May 09 2014 12:20:30
%S A083055 1,1,1,1,1,2,2,3,3,3,4,4,5,5,6,6,6,7,7,8,8,8,8,8,9,9,10,10,10,10,10,
%T A083055 11,11,12,12,12,13,13,14,14,14,14,14,15,15,16,16,16,16,16,17,17,18,18,
%U A083055 18,18,18,19,19,20,20,20,21,21,22,22,22,22,22,23,23,24,24,24,24,24,25,25
%N A083055 a(n) = cardinality{ k<=n / A083054(k)=1}.
%H A083055 Boris Gourevitch, <a href="http://membres.lycos.fr/bgourevitch/temporaires/benoit/sqrt3fractal.jpg">Graph of A083057</a>
%F A083055 a(n) = n/3 + O(n) (it seems O(n) could be replaced with O(log(n))).
%o A083055 (PARI) {a(n)=if(n<1,0, sum(k=1,n,sqrtint(3*k^2)-3*sqrtint(k^2\3)==1))} /* _Michael Somos_, Aug 31 2006 */
%Y A083055 Cf. A083038, A083054, A083056, A083057.
%K A083055 nonn
%O A083055 1,6
%A A083055 _Benoit Cloitre_, Apr 18 2003