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A184278
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Number of distinct n X n toroidal 0..2 arrays.
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2
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3, 27, 2211, 2691711, 33891544611, 4169295457320267, 4883659780216684279491, 53651309692070594433108320631, 5474401089420219382077156686715199875, 5153775207320113310364632834595843483435609099, 44553974378043749018508590814287728257805180848046070883
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = (1/(n^2)) * Sum_{c|n} Sum_{d|n} phi(c) * phi(d) * 3^(n^2/lcm(c,d)). - Andrew Howroyd, Sep 27 2017
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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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