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A267524 Binary representation of the middle column of the "Rule 139" elementary cellular automaton starting with a single ON (black) cell. 1
1, 10, 100, 1001, 10011, 100111, 1001111, 10011111, 100111111, 1001111111, 10011111111, 100111111111, 1001111111111, 10011111111111, 100111111111111, 1001111111111111, 10011111111111111, 100111111111111111, 1001111111111111111, 10011111111111111111 (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

S. Wolfram, A New Kind of Science

Index entries for sequences related to cellular automata

Index to Elementary Cellular Automata

FORMULA

Conjectures from Colin Barker, Jan 16 2016 and Apr 19 2019: (Start)

a(n) = 11*a(n-1)-10*a(n-2) for n>1.

G.f.: (1-x+x^3) / ((1-x)*(1-10*x)).

(End)

MATHEMATICA

rule=139; 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. A267520, A054135.

Sequence in context: A215254 A262863 A267156 * A259883 A242808 A304453

Adjacent sequences:  A267521 A267522 A267523 * A267525 A267526 A267527

KEYWORD

nonn,easy,changed

AUTHOR

Robert Price, Jan 16 2016

STATUS

approved

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Last modified April 21 22:12 EDT 2019. Contains 322328 sequences. (Running on oeis4.)