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 A266247 Binary representation of the middle column of the "Rule 9" elementary cellular automaton starting with a single ON (black) cell. 1
 1, 10, 101, 1010, 10101, 101011, 1010110, 10101101, 101011010, 1010110101, 10101101010, 101011010101, 1010110101010, 10101101010101, 101011010101010, 1010110101010101, 10101101010101010, 101011010101010101, 1010110101010101010, 10101101010101010101 (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) = (-45000*(-1)^n+1000009*10^n-55000)/990000 for n>3. a(n) = 10*a(n-1)+a(n-2)-10*a(n-3) for n>2. G.f.: (1+x^5-x^6) / ((1-x)*(1+x)*(1-10*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]], {k, 1, rows}]  (* Binary Representation of Middle Column *) CROSSREFS Cf. A266243, A266248. Sequence in context: A056830 A280146 A279665 * A267443 A267879 A284137 Adjacent sequences:  A266244 A266245 A266246 * A266248 A266249 A266250 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 June 18 07:44 EDT 2019. Contains 324203 sequences. (Running on oeis4.)