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A266788
Decimal representation of the n-th iteration of the "Rule 61" elementary cellular automaton starting with a single ON (black) cell.
2
1, 3, 12, 87, 120, 1679, 976, 29823, 7808, 500735, 62464, 8200191, 499712, 132710399, 3997696, 2135425023, 31981568, 34263269375, 255852544, 548984061951, 2046820352, 8789919006719, 16374562816, 140688096231423, 130996502528, 2251404676694015, 1047972020224
OFFSET
0,2
FORMULA
Conjectures from Colin Barker, Jan 03 2016 and Apr 18 2019: (Start)
a(n) = 25*a(n-2)-152*a(n-4)+128*a(n-6) for n>10.
G.f.: (1+3*x-13*x^2+12*x^3-28*x^4-40*x^5-328*x^6+688*x^7+112*x^8 -768*x^9+256*x^10) / ((1-x)*(1+x)*(1-4*x)*(1+4*x)*(1-8*x^2)).
(End)
MATHEMATICA
rule=61; 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: A077047 A074505 A260912 * A039305 A174463 A367143
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 03 2016
STATUS
approved