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A267889
Binary representation of the n-th iteration of the "Rule 239" elementary cellular automaton starting with a single ON (black) cell.
2
1, 110, 11111, 1111111, 111111111, 11111111111, 1111111111111, 111111111111111, 11111111111111111, 1111111111111111111, 111111111111111111111, 11111111111111111111111, 1111111111111111111111111, 111111111111111111111111111, 11111111111111111111111111111
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 17 2019: (Start)
a(n) = 101*a(n-1)-100*a(n-2) for n>3.
G.f.: (1+9*x+101*x^2-100*x^3) / ((1-x)*(1-100*x)).
(End)
MATHEMATICA
rule=239; 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]]], {k, 1, rows}] (* Binary Representation of Rows *)
CROSSREFS
Cf. A267871.
Sequence in context: A193240 A267775 A267867 * A285696 A097580 A216786
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 21 2016
STATUS
approved