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 A064286 Number of cyclotomic cosets C of 2 mod 2n+1 such that -C = C. 3
 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; refs; listen; history; text; internal format)
 OFFSET 1,4 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 FORMULA A006694(n) = a(n) + 2*A064287(n). EXAMPLE 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. CROSSREFS Cf. A006694, A064287. Sequence in context: A327910 A242998 A140885 * A002471 A218622 A337621 Adjacent sequences:  A064283 A064284 A064285 * A064287 A064288 A064289 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 21 09:39 EST 2022. Contains 350476 sequences. (Running on oeis4.)