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A006447
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Consider a 2-D cellular automaton generated by the Schrandt-Ulam rule of A170896, but confined to a semi-infinite strip of width n, starting with one ON cell at the top left corner; a(n) is the period of the resulting structure.
(Formerly M0608)
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6
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1, 2, 3, 5, 5, 8, 13, 13, 13, 26, 13, 91, 13, 106, 106, 75, 93, 62, 80, 132, 337, 416, 62, 62, 62, 271, 34, 155, 525, 548, 1084, 115, 62, 558, 62, 1500, 2922, 124, 2958, 3374, 2323, 4183, 8073, 7925, 744, 2298, 434, 6700, 310, 23796, 12732, 26405
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OFFSET
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1,2
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COMMENTS
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Schrandt and Ulam remark that there seems to be no simple relation between n and a(n).
The original report included two further terms, but they were omitted from the published version, so are presumably unreliable.
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Table of n, a(n) for n=1..52.
J. T. Butler, Letter to N. J. A. Sloane, Jun. 1975.
R. G. Schrandt and S. M. Ulam, On recursively defined geometric objects and patterns of growth, Los Alamos Scientific Laboratory, Report LA-3762, Aug 16 1967; published in A. W. Burks, editor, Essays on Cellular Automata. Univ. Ill. Press, 1970, pp. 238ff. [Link supplied by Laurinda J. Alcorn, Jan 09 2010]
Index entries for sequences related to cellular automata
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CROSSREFS
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Sequence in context: A204207 A287919 A138181 * A014237 A033885 A053079
Adjacent sequences: A006444 A006445 A006446 * A006448 A006449 A006450
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane
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EXTENSIONS
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Entry revised by N. J. A. Sloane, Jan 09 2010
More terms from Sean A. Irvine, Apr 13 2017
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STATUS
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approved
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