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A168649
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a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d).
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0
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2, 6, 168, 16320, 6710880, 11453201760, 80421421917312, 2305843008676823040, 268650182136584246132736, 126765060022822827559679531520, 241677817415439249618874010960062464, 1858395433210885261794249658823668075069440
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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)*Sum_{d|n} moebius(n/d)*(2^n)^d.
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MATHEMATICA
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a[n_] := DivisorSum[n, MoebiusMu[#] * 2^(n^2/#) &] / n; Array[a, 10] (* Amiram Eldar, Aug 18 2023 *)
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PROG
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(PARI) a(n)=(1/n)*sumdiv(n, d, moebius(d)*2^(n^2/d))
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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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