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A267805
Decimal representation of the n-th iteration of the "Rule 214" elementary cellular automaton starting with a single ON (black) cell.
1
1, 7, 23, 103, 375, 1639, 6007, 26215, 96119, 419431, 1537911, 6710887, 24606583, 107374183, 393705335, 1717986919, 6299285367, 27487790695, 100788565879, 439804651111, 1612617054071, 7036874417767, 25801872865143, 112589990684263, 412829965842295
OFFSET
0,2
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
FORMULA
Conjectures from Colin Barker, Jan 22 2016 and Apr 20 2019: (Start)
a(n) = 17*a(n-2)-16*a(n-4) for n>3.
G.f.: (1+7*x+6*x^2-16*x^3) / ((1-x)*(1+x)*(1-4*x)*(1+4*x)).
(End)
MATHEMATICA
rule=214; 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. A071040.
Sequence in context: A217233 A316734 A096327 * A154113 A340889 A053706
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 20 2016
STATUS
approved