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Search: id:A064286
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| A064286 |
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Number of cyclotomic cosets C of 2 mod 2n+1 such that -C = C. |
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+0
3
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| 1, 1, 0, 2, 1, 1, 2, 2, 1, 1, 0, 2, 3, 1, 0, 4, 1, 1, 2, 2, 3, 3, 0, 0, 3, 1, 2, 4, 1, 1, 2, 6, 1, 1, 0, 0, 3, 1, 0, 4, 1, 3, 2, 0, 1, 1, 2, 2, 7, 1, 0, 2, 1, 3, 2, 4, 1, 3, 2, 2, 3, 3, 0, 10, 1, 1, 4, 2, 1, 1, 2, 6, 1, 1, 0, 4, 1, 3, 2, 0, 1, 5, 0, 2, 11, 1, 2, 4, 1, 1, 2, 6, 3, 3, 0, 2, 7, 1, 0, 4, 1, 11, 2, 4
(list; graph; listen)
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OFFSET
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1,4
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REFERENCES
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F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier/North Holland, 1977, pp. 104-105.
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LINKS
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Ray Chandler, Table of n, a(n) for n=1..10000
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EXAMPLE
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Mod 15 there are 4 cosets: {1, 2, 4, 8}, {3, 6, 12, 9}, {5, 10}, {7, 14, 13, 11}. Only the cosets {3, 6, 12, 9} and {5, 10} have the desired property. So a(7) = 2.
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CROSSREFS
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A006694(n) = a(n) + 2*A064287(n).
Sequence in context: A093324 A034798 A115236 this_sequence A002471 A091243 A037826
Adjacent sequences: A064283 A064284 A064285 this_sequence A064287 A064288 A064289
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KEYWORD
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nonn,nice,easy
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AUTHOR
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njas, Sep 25 2001
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Apr 25 2008
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