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A267367 Decimal representation of the middle column of the "Rule 126" elementary cellular automaton starting with a single ON (black) cell. 1
1, 3, 6, 13, 26, 52, 104, 209, 418, 836, 1672, 3344, 6688, 13376, 26752, 53505, 107010, 214020, 428040, 856080, 1712160, 3424320, 6848640, 13697280, 27394560, 54789120, 109578240, 219156480, 438312960, 876625920, 1753251840, 3506503681, 7013007362 (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

Eric Weisstein's World of Mathematics, Rule 126

S. Wolfram, A New Kind of Science

Index entries for sequences related to cellular automata

Index to Elementary Cellular Automata

MAPLE

A267367 := proc(n) local i, s, z; s := 0; i := n; z := 1;

while 0 <= i do s := s+2^i; i := i-z; z := z+z od; s end:

seq(A267367(n), n=0..32); # Peter Luschny, Dec 02 2017

MATHEMATICA

rule=126; 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 *)

PROG

(Python)

def A267367(n):

    i, s, z = n, 0, 1

    while 0 <= i: s += 1<<i; i -= z; z += z

    return s

print([A267367(n) for n in range(33)]) # Peter Luschny, Dec 02 2017

CROSSREFS

Cf. A001855, A071035, A267365.

Sequence in context: A032198 A079941 A255125 * A265385 A019300 A072762

Adjacent sequences:  A267364 A267365 A267366 * A267368 A267369 A267370

KEYWORD

nonn,easy

AUTHOR

Robert Price, Jan 13 2016

STATUS

approved

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Last modified November 16 21:32 EST 2018. Contains 317275 sequences. (Running on oeis4.)