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Search: id:A091704
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| A091704 |
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Number of Barker codes of length n up to reversals and negations. |
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+0
3
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| 2, 1, 2, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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2,1
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COMMENT
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It is conjectured that there are no Barker codes of length > 13.
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REFERENCES
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R. H. Barker, Group synchronizing of binary digital sequences, in "Communication Theory", Butterworth, London, 1953, pp. 273-287.
H. D. Lueke, Korrelationssignale, Springer 1992.
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LINKS
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Eric Weisstein's World of Mathematics, Barker Code
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EXAMPLE
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{{+, +}, {+, -}}, {{+, +, -}}, {{+, +, +, -}, {+, +, -, +}}, {{+, +, +, -, +}}, {{+, +, +, -, -, +, -}}, {{+, +, +, -, -, -, +, -, -, +, -}}, {{+, +, +, +, +, -, -, +, +, -, +, -, +}}
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CROSSREFS
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Cf. A011758, A011759.
Sequence in context: A105661 A082451 A121362 this_sequence A123739 A165575 A165582
Adjacent sequences: A091701 A091702 A091703 this_sequence A091705 A091706 A091707
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KEYWORD
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nonn
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AUTHOR
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Eric Weisstein (eric(AT)weisstein.com), Jan 30, 2004
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EXTENSIONS
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Comment changed by N. J. A. Sloane (njas(AT)research.att.com), Feb 03 2005
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