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A263806
Decimal representation of the n-th iteration of the "Rule 157" elementary cellular automaton starting with a single ON (black) cell.
2
1, 3, 7, 47, 95, 703, 1407, 11007, 22015, 175103, 350207, 2797567, 5595135, 44744703, 89489407, 715849727, 1431699455, 11453333503, 22906667007, 183252287487, 366504574975, 2932032405503, 5864064811007, 46912501710847, 93825003421695, 750599960264703
OFFSET
0,2
FORMULA
Conjectures from Colin Barker, Jan 20 2016 and Apr 17 2019: (Start)
a(n) = 3*a(n-1)+14*a(n-2)-48*a(n-3)+32*a(n-4) for n>4.
G.f.: (1-16*x^2+32*x^3-32*x^4) / ((1-x)*(1-2*x)*(1-4*x)*(1+4*x)).
(End)
MATHEMATICA
rule=157; 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: A132565 A129518 A007670 * A074714 A064457 A318087
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 17 2016
STATUS
approved