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 A064287 Number of cyclotomic cosets C of 2 mod 2n+1 such that -C is not equal to C, divided by 2. 5
 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; refs; listen; history; text; internal format)
 OFFSET 1,10 REFERENCES F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier/North Holland, 1977, pp. 104-105. LINKS Ray Chandler, Table of n, a(n) for n = 1..10000 EXAMPLE 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. CROSSREFS A006694(n) = A064286(n) + 2*a(n). Sequence in context: A339829 A177517 A227819 * A196389 A128206 A103294 Adjacent sequences:  A064284 A064285 A064286 * A064288 A064289 A064290 KEYWORD nonn,nice,easy AUTHOR N. J. A. Sloane, Sep 25 2001 EXTENSIONS Extended by Ray Chandler, Apr 25 2008 STATUS approved

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Last modified January 22 21:47 EST 2022. Contains 350504 sequences. (Running on oeis4.)