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 A071030 #28 Jan 30 2016 14:39:07 %S A071030 1,1,1,1,1,0,0,0,1,1,1,1,0,1,1,1,1,0,0,0,1,0,0,0,1,1,1,1,0,1,1,1,0,1, %T A071030 1,1,1,0,0,0,1,0,0,0,1,0,0,0,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,0,0,0, %U A071030 1,0,0,0,1,0,0,0,1,0,0,0,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1 %N A071030 Triangle read by rows giving successive states of cellular automaton generated by "Rule 54". %C A071030 Row n has length 2n+1. %C A071030 Even rows r sum to r/2 + 1, odd rows r sum to 3r to produce the sequence {1, 3, 2, 6, 3, 9, 4, 12, ...} = A064455(n + 1). - _Michael De Vlieger_, Oct 07 2015 %D A071030 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; Chapter 3. %H A071030 Michael De Vlieger, <a href="/A071030/b071030.txt">Table of n, a(n) for n = 0..10000</a> %H A071030 Michael De Vlieger, <a href="/A071030/a071030.png">Visualization of rows 0 - 31 of Rule 54</a> %H A071030 S. Wolfram, <a href="http://dx.doi.org/10.1103/RevModPhys.55.601">Statistical mechanics of cellular automata</a>, Rev. Mod. Phys., 55 (1983), 601--644. %H A071030 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a> %H A071030 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a> %H A071030 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %e A071030 From _Michael De Vlieger_, Oct 07 2015: (Start) %e A071030 First 12 rows, replacing "0" with "." for better visibility of ON cells: %e A071030 1 %e A071030 1 1 1 %e A071030 1 . . . 1 %e A071030 1 1 1 . 1 1 1 %e A071030 1 . . . 1 . . . 1 %e A071030 1 1 1 . 1 1 1 . 1 1 1 %e A071030 1 . . . 1 . . . 1 . . . 1 %e A071030 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 %e A071030 1 . . . 1 . . . 1 . . . 1 . . . 1 %e A071030 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 %e A071030 1 . . . 1 . . . 1 . . . 1 . . . 1 . . . 1 %e A071030 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 . 1 1 1 %e A071030 1 . . . 1 . . . 1 . . . 1 . . . 1 . . . 1 . . . 1 %e A071030 (End) %t A071030 clip[lst_] := Block[{p = Flatten@ Position[lst, 1]}, Take[lst, {Min@ p, Max@ p}]]; clip /@ CellularAutomaton[54, {{1}, 0}, 8] // Flatten (* _Michael De Vlieger_, Oct 07 2015 *) %Y A071030 Cf. A064455. See A118108 and A118109 for two other versions of this sequence. %K A071030 nonn,tabf %O A071030 0,1 %A A071030 _Hans Havermann_, May 26 2002 %E A071030 Corrected by _Hans Havermann_, Jan 07 2012