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 A079686 #14 Mar 21 2013 16:42:31
%S A079686 0,1,0,1,1,2,0,1,2,3,1,3,0,2,3,2,2,5,1,4,0,1,5,1,4,3,3,5,2,6,1,5,0,1,
%T A079686 6,4,5,2,4,5,3,6,2,9,1,6,0,1,9,0,8,0,7,4,6,6,5,4,4,6,3,8,2,11,1,7,0,1,
%U A079686 11,0,10,2,9,2,8,2
%N A079686 Start with 0; at n-th step, write down what is in the sequence so far.
%C A079686 Start with the highest value currently in the sequence and count down to zero.
%H A079686 Nathaniel Johnston, <a href="/A079686/b079686.txt">Table of n, a(n) for n = 0..10000</a>
%e A079686 After the sequence is "0, 1, 0, 1, 1, 2, 0", we see one "2", three "1"s, and three "0"s, so we add 1, 2, 3, 1, 3, 0 to the sequence.
%t A079686 s={0}; Do[s=Flatten[{s, {Count[s,#],#}&/@Range[Max[s],0,-1]}], {60}]; s (* _Peter J. C. Moses_, Mar 21 2013 *)
%o A079686 (MATLAB) a=[0];c=2;d=2; for j=1:7 for k=max(a):-1:0 a(c)=size(find(a(1:d-1)==k),2); a(c+1)=k; c=c+2; end; d=c; end; a' % Nathaniel Johnston, Apr 25 2011
%Y A079686 Cf. A005150. For other versions see A051120, A079668, A055186.
%K A079686 nonn,easy,base
%O A079686 0,6
%A A079686 _N. J. A. Sloane_ Jan 26 2003
%E A079686 a(13) - a(75) from _Nathaniel Johnston_, Apr 25 2011