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Search: id:A064287
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| A064287 |
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Number of cyclotomic cosets C of 2 mod 2n+1 such that -C is not equal to C, divided by 2. |
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+0
5
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| 0, 0, 1, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 0, 3, 0, 2, 0, 1, 0, 0, 2, 1, 2, 2, 0, 1, 0, 0, 0, 5, 0, 0, 2, 1, 4, 2, 2, 1, 0, 0, 4, 1, 4, 4, 6, 1, 0, 0, 0, 1, 6, 0, 0, 1, 0, 2, 4, 3, 0, 2, 0, 9, 0, 0, 4, 3, 0, 0, 2, 1, 0, 4, 0, 5, 4, 6, 0, 1, 4, 0, 4, 1, 0, 0, 0, 3, 0, 0, 0, 1, 0, 2, 8, 1, 0, 6, 0, 1, 0, 2, 0, 3, 0, 0
(list; graph; listen)
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OFFSET
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1,10
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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 {1, 2, 4, 8} and {7, 14, 13, 11} have the desired property, so a(7) = 2/2 = 1.
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CROSSREFS
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A006694(n) = A064286(n) + 2*a(n).
Sequence in context: A116402 A093323 A106278 this_sequence A128206 A103294 A079680
Adjacent sequences: A064284 A064285 A064286 this_sequence A064288 A064289 A064290
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KEYWORD
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nonn,nice,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), 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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