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A267523
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Binary representation of the n-th iteration of the "Rule 139" elementary cellular automaton starting with a single ON (black) cell.
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1
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1, 100, 10011, 1001111, 100111111, 10011111111, 1001111111111, 100111111111111, 10011111111111111, 1001111111111111111, 100111111111111111111, 10011111111111111111111, 1001111111111111111111111, 100111111111111111111111111, 10011111111111111111111111111
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 101*a(n-1)-100*a(n-2) for n>2.
G.f.: (1-x+11*x^2) / ((1-x)*(1-100*x)).
(End)
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MATHEMATICA
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rule=139; 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 *)
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PROG
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(Python) print([100**n + int(100**(n-1))//9 for n in range(50)]) # Karl V. Keller, Jr., Sep 15 2021
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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