Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #17 Apr 18 2019 10:57:06
%S 1,100,11010,1111010,111111010,11111111010,1111111111010,
%T 111111111111010,11111111111111010,1111111111111111010,
%U 111111111111111111010,11111111111111111111010,1111111111111111111111010,111111111111111111111111010,11111111111111111111111111010
%N Binary representation of the n-th iteration of the "Rule 227" elementary cellular automaton starting with a single ON (black) cell.
%D S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
%H Robert Price, <a href="/A267846/b267846.txt">Table of n, a(n) for n = 0..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%F Conjectures from _Colin Barker_, Jan 21 2016: (Start)
%F a(n) = 101*a(n-1)-100*a(n-2) for n>3.
%F G.f.: (1-x+1010*x^2+9000*x^3) / ((1-x)*(1-100*x)).
%F (End)
%t rule=227; rows=20; ca=CellularAutomaton[rule,{{1},0},rows-1,{All,All}]; (* Start with single black cell *) catri=Table[Take[ca[[k]],{rows-k+1,rows+k-1}],{k,1,rows}]; (* Truncated list of each row *) Table[FromDigits[catri[[k]]],{k,1,rows}] (* Binary Representation of Rows *)
%Y Cf. A267845.
%K nonn
%O 0,2
%A _Robert Price_, Jan 21 2016