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 A266248 Decimal representation of the middle column of the "Rule 9" elementary cellular automaton starting with a single ON (black) cell. 3
 1, 2, 5, 10, 21, 43, 86, 173, 346, 693, 1386, 2773, 5546, 11093, 22186, 44373, 88746, 177493, 354986, 709973, 1419946, 2839893, 5679786, 11359573, 22719146, 45438293, 90876586, 181753173, 363506346, 727012693, 1454025386, 2908050773, 5816101546, 11632203093 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55. LINKS Robert Price, Table of n, a(n) for n = 0..999 Eric Weisstein's World of Mathematics, Elementary Cellular Automaton FORMULA Conjectures from Colin Barker, Dec 28 2015 and Apr 14 2019: (Start) a(n) = (65*2^n-8*((-1)^n+3))/48 for n>3. a(n) = 2*a(n-1)+a(n-2)-2*a(n-3) for n>2. G.f.: (1+x^5-x^6) / ((1-x)*(1+x)*(1-2*x)). (End) MATHEMATICA rule=9; 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 *) CROSSREFS Cf. A266243. Sequence in context: A279668 A245747 A032283 * A027437 A267444 A267880 Adjacent sequences:  A266245 A266246 A266247 * A266249 A266250 A266251 KEYWORD nonn,easy AUTHOR Robert Price, Dec 25 2015 EXTENSIONS Conjectures from Colin Barker, Apr 14 2019 STATUS approved

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Last modified May 25 15:20 EDT 2019. Contains 323571 sequences. (Running on oeis4.)