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 A013189 #13 Apr 04 2015 02:40:34
%S A013189 1,4,4,4,4,9,9,9,9,16,16,16,16,25,25,25,25,36,36,36,36,36,36,36,36,36,
%T A013189 49,49,49,49,49,49,49,49,49,64,64,64,64,64,64,64,64,64,81,81,81,81,81,
%U A013189 81,81,81,81,100,100,100,100,100,100,100,100,100,100,100,100,100,100
%N A013189 All terms are squares and a(n) is length of n-th run.
%C A013189 Golomb's sequence using squares. - _Benoit Cloitre_, Apr 20 2003
%H A013189 Ivan Neretin, <a href="/A013189/b013189.txt">Table of n, a(n) for n = 1..10000</a>
%F A013189 n-th term, divided by n, tends to square root of two.
%t A013189 f[s_] := Join@@Table[i^2, {i, Length[s]}, {s[[i]]}]; Nest[f, {1, 4}, 3]
%Y A013189 Cf. A001462, A080605, A080606, A080607.
%K A013189 nonn,easy
%O A013189 1,2
%A A013189 _James Propp_