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A267450 Decimal representation of the n-th iteration of the "Rule 131" elementary cellular automaton starting with a single ON (black) cell. 1
1, 4, 18, 72, 294, 1168, 4686, 18728, 74886, 299632, 1198414, 4793384, 19174278, 76696176, 306782542, 1227136040, 4908536710, 19634129520, 78536565070, 314146200616, 1256584663942, 5026339031664, 20105355649358, 80421421489192, 321685688963974 (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

Empirical g.f.: (1+2*x^2-8*x^3+5*x^4-24*x^5+12*x^6-56*x^7+32*x^8) / ((1-x)*(1+x)*(1-2*x)*(1-4*x)*(1+x^2)*(1+2*x+4*x^2)). - Colin Barker, Jan 15 2016 and Apr 19 2019

MATHEMATICA

rule=131; 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 *) Table[FromDigits[catri[[k]], 2], {k, 1, rows}] (* Decimal Representation of Rows *)

CROSSREFS

Cf. A267418.

Sequence in context: A218892 A307566 A117615 * A199524 A083693 A123476

Adjacent sequences:  A267447 A267448 A267449 * A267451 A267452 A267453

KEYWORD

nonn

AUTHOR

Robert Price, Jan 15 2016

STATUS

approved

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Last modified September 22 00:42 EDT 2020. Contains 337276 sequences. (Running on oeis4.)