A266625 - OEIS

%I #6 Jan 02 2016 03:59:30

%S 1,3,7,14,28,57,115,230,460,921,1842,3685,7371,14743,29486,58973,

%T 117947,235894,471789,943579,1887159,3774318,7548637,15097274,

%U 30194548,60389097,120778195,241556391,483112783,966225567,1932451134,3864902268,7729804536

%N Decimal representation of the middle column of the "Rule 45" elementary cellular automaton starting with a single ON (black) cell.

%D S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.

%H G. C. Greubel, <a href="/A266625/b266625.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>

%t rule=45; 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 *) mc=Table[catri[[k]][[k]],{k,1,rows}]; (* Keep only middle cell from each row *) Table[FromDigits[Take[mc,k],2],{k,1,rows}]  (* Binary Representation of Middle Column *)

%Y Cf. A266619.

%K nonn,easy

%O 0,2

%A _Robert Price_, Jan 01 2016