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”).

A267054
Binary representation of the n-th iteration of the "Rule 93" elementary cellular automaton starting with a single ON (black) cell.
2
1, 11, 10100, 101111, 101010000, 1010111111, 1010101000000, 10101011111111, 10101010100000000, 101010101111111111, 101010101010000000000, 1010101010111111111111, 1010101010101000000000000, 10101010101011111111111111, 10101010101010100000000000000
OFFSET
0,2
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
FORMULA
Conjectures from Colin Barker, Jan 10 2016 and Apr 19 2019: (Start)
a(n) = 10101*a(n-2)-1010100*a(n-4)+1000000*a(n-6) for n>5.
G.f.: (1+11*x-x^2-10000*x^3-100000*x^5) / ((1-x)*(1+x)*(1-10*x)*(1+10*x)*(1-100*x)*(1+100*x)).
(End)
MATHEMATICA
rule=93; 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
Sequence in context: A204574 A267801 A050647 * A082265 A161761 A114754
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 09 2016
EXTENSIONS
Removed an unjustified claim that Colin Barker's conjectures are correct. Removed a program based on a conjecture. - Michael De Vlieger, Jun 13 2022
STATUS
approved