login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A267127
Binary representation of the n-th iteration of the "Rule 99" elementary cellular automaton starting with a single ON (black) cell.
1
1, 100, 1010, 1101001, 1100100, 11101010011, 1101001000, 111101100100111, 1101010010000, 1111101101001001111, 1101100100100000, 11111101101010010011111, 1101101001001000000, 111111101101100100100111111, 1101101010010010000000, 1111111101101101001001001111111
OFFSET
0,2
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
FORMULA
Empirical g.f.: (1 +100*x -10001*x^2 -1099*x^3 -10000*x^5 -899991000*x^6 +10000000*x^7 +10911000000*x^8 -20000000000*x^10) / ((1 -x)*(1 +x)*(1 -10*x)*(1 -100*x)*(1 +100*x)*(1 -10*x^2)*(1 +10*x +100*x^2)*(1 -1000*x^2)). - Colin Barker, Jan 11 2016 and Apr 19 2019
MATHEMATICA
rule=99; 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. A267126.
Sequence in context: A379268 A001737 A266838 * A266893 A267153 A343294
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 10 2016
STATUS
approved