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A347251
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a(n) = Sum_{d|n} mu(d)*mu(n/d)*d^n.
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2
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1, -5, -28, 16, -3126, 47450, -823544, 0, 19683, 10009766650, -285311670612, -2176786432, -302875106592254, 11112685048647250, 437893920912786408, 0, -827240261886336764178, -101560344088905, -1978419655660313589123980, -100000000000001048576
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OFFSET
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1,2
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LINKS
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FORMULA
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If p is prime, a(p) = -1 - p^p.
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MATHEMATICA
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a[n_] := DivisorSum[n, MoebiusMu[#] * MoebiusMu[n/#] * #^n &]; Array[a, 20] (* Amiram Eldar, Aug 24 2021 *)
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PROG
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(PARI) a(n) = sumdiv(n, d, moebius(d)*moebius(n/d)*d^n);
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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