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 A266445 Binary representation of the middle column of the "Rule 25" elementary cellular automaton starting with a single ON (black) cell. 1
 1, 10, 100, 1000, 10001, 100010, 1000101, 10001010, 100010101, 1000101011, 10001010110, 100010101100, 1000101011000, 10001010110001, 100010101100010, 1000101011000101, 10001010110001010, 100010101100010101, 1000101011000101010, 10001010110001010101 (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..1000 Eric Weisstein's World of Mathematics, Elementary Cellular Automaton FORMULA Conjectures from Colin Barker, Dec 31 2015 and Apr 16 2019: (Start) a(n) = (-9*(-1)^n+9901000008901*2^(n-10)*5^(n-11)-11)/198 for n>10 G.f.: (1-x^2+x^4+x^9-x^10-x^11+x^13) / ((1-x)*(1+x)*(1-10*x)). (End) MATHEMATICA rule=25; 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. A266441, A266466. Sequence in context: A138824 A273495 A267044 * A266896 A282981 A282951 Adjacent sequences:  A266442 A266443 A266444 * A266446 A266447 A266448 KEYWORD nonn,easy AUTHOR Robert Price, Dec 29 2015 STATUS approved

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Last modified September 20 04:04 EDT 2020. Contains 337264 sequences. (Running on oeis4.)