A070886 - OEIS

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A070886

Triangle read by rows giving successive states of cellular automaton generated by "Rule 90".

1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0

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OFFSET

0,1

COMMENTS

If either neighbor is 1 then new state is 1, otherwise new state is 0.

Row n has length 2n+1.

Rules #18, #26, #82, #90, #146, #154, #210, #218 all give rise to this sequence. - Hans Havermann

REFERENCES

S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 25.

LINKS

Robert Price, Table of n, a(n) for n = 0..9999

Eric Weisstein's World of Mathematics, Rule 90

S. Wolfram, A New Kind of Science

Index to Elementary Cellular Automata

Index entries for sequences related to cellular automata

EXAMPLE

1; 1,0,1; 1,0,0,0,1; 1,0,1,0,1,0,1; ...

MATHEMATICA

rows = 10; ca = CellularAutomaton[90, {{1}, 0}, rows-1]; Flatten[ Table[ca[[k, rows-k+1 ;; rows+k-1]], {k, 1, rows}]] (* Jean-François Alcover, May 24 2012 *)

CROSSREFS

Cf. A070950, A070887. Alternate rows of A047999. Interpreted as binary numbers: A038183. Interpreted as Zeckendorf-expansions: A048757. Drawn as binary trees: A080263.

Sequence in context: A145099 A374045 A205083 * A262808 A217206 A189097

Adjacent sequences: A070883 A070884 A070885 * A070887 A070888 A070889

KEYWORD

nonn,tabf,nice,easy

AUTHOR

N. J. A. Sloane, May 19 2002

EXTENSIONS

More terms from Hans Havermann, May 26 2002

STATUS

approved