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A372881
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a(n) = Sum_{j=1..n} Sum_{k=1..n} gcd(j*k,n).
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2
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1, 7, 19, 44, 61, 133, 127, 256, 297, 427, 331, 836, 469, 889, 1159, 1408, 817, 2079, 1027, 2684, 2413, 2317, 1519, 4864, 2825, 3283, 4131, 5588, 2437, 8113, 2791, 7424, 6289, 5719, 7747, 13068, 3997, 7189, 8911, 15616, 4921, 16891, 5419, 14564, 18117, 10633, 6487, 26752
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OFFSET
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1,2
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LINKS
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PROG
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(PARI) a(n) = sum(j=1, n, sum(k=1, n, gcd(j*k, n)));
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CROSSREFS
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KEYWORD
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nonn,mult
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AUTHOR
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STATUS
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approved
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