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Search: id:A007040
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| A007040 |
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Number of cyclic n-bit binary strings containing no runs of length >2.
(Formerly M0354)
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+0
2
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| 2, 2, 6, 6, 10, 20, 28, 46, 78, 122, 198, 324, 520, 842, 1366, 2206, 3570, 5780, 9348, 15126, 24478, 39602, 64078, 103684, 167760, 271442, 439206, 710646, 1149850, 1860500, 3010348, 4870846, 7881198, 12752042, 20633238, 33385284, 54018520
(list; graph; listen)
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OFFSET
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1,1
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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).
Z. Agur et al., The number of fixed points of the majority rule, Discr. Math., 70 (1988), 295-302.
Moser, W. O. J.; Cyclic binary strings without long runs of like (alternating) bits. Fibonacci Quart. 31 (1993), no. 1, 2-6.
A. McLeod and W. O. J. Moser, Counting cyclic binary strings, Math. Mag., 80 (No. 1, 2007), 29-37.
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FORMULA
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a(n) = a(n-2) + 2*a(n-3) + a(n-4), n >= 7 (David W. Wilson (davidwwilson(AT)comcast.net)).
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CROSSREFS
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Cf. A007039.
Sequence in context: A162776 A032302 A032214 this_sequence A032139 A032043 A028476
Adjacent sequences: A007037 A007038 A007039 this_sequence A007041 A007042 A007043
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from David W. Wilson (davidwwilson(AT)comcast.net)
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