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A267042 Decimal representation of the n-th iteration of the "Rule 91" elementary cellular automaton starting with a single ON (black) cell. 2
1, 5, 10, 99, 124, 1935, 496, 32319, 1984, 522495, 7936, 8381439, 31744, 134189055, 126976, 2147368959, 507904, 34359279615, 2031616, 549753978879, 8126464, 8796085682175, 32505856, 140737458995199, 130023424, 2251799696244735, 520093696, 36028796549201919 (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
Eric Weisstein's World of Mathematics, Elementary Cellular Automaton
FORMULA
Conjectures from Colin Barker, Jan 10 2016: (Start)
a(n) = 21*a(n-2)-84*a(n-4)+64*a(n-6) for n>8.
G.f.: (1+5*x-11*x^2-6*x^3-2*x^4+276*x^5-1332*x^6-320*x^7+1344*x^8) / ((1-x)*(1+x)*(1-2*x)*(1+2*x)*(1-4*x)*(1+4*x)).
(End)
MATHEMATICA
rule=91; 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
Sequence in context: A120598 A200983 A344140 * A119137 A048360 A357565
KEYWORD
nonn
AUTHOR
Robert Price, Jan 09 2016
EXTENSIONS
Removed an unjustified claim that Colin Barker's conjectures are correct. Removed a program based on a conjecture. - Michael De Vlieger, Jun 13 2022
STATUS
approved

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Last modified June 17 07:23 EDT 2024. Contains 373433 sequences. (Running on oeis4.)