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A266326
Triangle read by rows giving successive states of cellular automaton generated by "Rule 20" initiated with a single ON (black) cell.
2
1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0
OFFSET
0
COMMENTS
Row n has length 2n+1.
This sequence is also generated by Rules 52, 148 and 180.
REFERENCES
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
EXAMPLE
The first ten rows:
1
0 1 1
0 0 0 0 1
0 0 0 0 0 1 1
0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 1 1
0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
MATHEMATICA
rule=20; 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 *) Flatten[catri] (* Triangle Representation of CA *)
CROSSREFS
Sequence in context: A133101 A258769 A266377 * A185295 A214295 A145377
KEYWORD
nonn,tabf,easy
AUTHOR
Robert Price, Dec 27 2015
STATUS
approved