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 A056463 Number of primitive (aperiodic) palindromes using exactly two different symbols. 4
 0, 0, 2, 2, 6, 4, 14, 12, 28, 24, 62, 54, 126, 112, 246, 240, 510, 476, 1022, 990, 2030, 1984, 4094, 4020, 8184, 8064, 16352, 16254, 32766, 32484, 65534, 65280, 131006, 130560, 262122, 261576, 524286, 523264, 1048446, 1047540, 2097150, 2094988, 4194302, 4192254 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2] LINKS Andrew Howroyd, Table of n, a(n) for n = 1..1000 FORMULA a(n) = Sum_{d|n} mu(d)*A056453(n/d). G.f.: Sum_{k>=1} mu(k)*2*x^(3*k)/((1 - 2*x^(2*k))*(1 - x^k)). - Andrew Howroyd, Sep 29 2019 PROG (PARI) seq(n)={Vec(sum(k=1, n\3, moebius(k)*2*x^(3*k)/((1 - 2*x^(2*k))*(1 - x^k)) + O(x*x^n)), -n)} \\ Andrew Howroyd, Sep 29 2019 CROSSREFS Column 2 of A327873. Cf. A056453, A056458. Sequence in context: A321451 A285943 A100495 * A309694 A325263 A005992 Adjacent sequences:  A056460 A056461 A056462 * A056464 A056465 A056466 KEYWORD nonn AUTHOR EXTENSIONS Terms a(32) and beyond from Andrew Howroyd, Sep 28 2019 STATUS approved

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Last modified January 26 14:08 EST 2020. Contains 331280 sequences. (Running on oeis4.)