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A267851
Decimal representation of the n-th iteration of the "Rule 229" elementary cellular automaton starting with a single ON (black) cell.
1
1, 2, 30, 126, 510, 2046, 8190, 32766, 131070, 524286, 2097150, 8388606, 33554430, 134217726, 536870910, 2147483646, 8589934590, 34359738366, 137438953470, 549755813886, 2199023255550, 8796093022206, 35184372088830, 140737488355326, 562949953421310
OFFSET
0,2
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
FORMULA
Conjectures from Colin Barker, Jan 21 2016: (Start)
a(n) = 5*a(n-1)-4*a(n-2) for n>3.
G.f.: (1-3*x+24*x^2-16*x^3) / ((1-x)*(1-4*x)).
(End)
Conjecture: a(n) = 2*(4^n - 1) for n>1. - Colin Barker, Nov 26 2016
MATHEMATICA
rule=229; 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. A267848.
Sequence in context: A157870 A285991 A078838 * A089288 A232602 A154413
KEYWORD
nonn
AUTHOR
Robert Price, Jan 21 2016
STATUS
approved