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A056460
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Number of primitive (aperiodic) palindromes using a maximum of four different symbols.
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4
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4, 0, 12, 12, 60, 48, 252, 240, 1008, 960, 4092, 4020, 16380, 16128, 65460, 65280, 262140, 261072, 1048572, 1047540, 4194036, 4190208, 16777212, 16772880, 67108800, 67092480, 268434432, 268419060, 1073741820, 1073675280, 4294967292, 4294901760, 17179865076, 17179607040, 68719476420
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listen;
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OFFSET
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1,1
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REFERENCES
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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]
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LINKS
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FORMULA
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a(n) = Sum_{d|n} mu(d)*A056450(n/d).
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PROG
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(PARI) a(n) = sumdiv(n, d, moebius(d)*(3*2^(n/d)-(-2)^(n/d))/2);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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