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A158947
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Inverse Euler transform of A156217.
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2
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1, 4, 21, 598, 1555, 497652, 299593, 320361028, 1178277701, 357046721884, 67546215517, 19351522090518670, 61054982558011, 1502551437369035044, 33657152197069739919, 45463945109198918808616, 128583032925805678351
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internal format)
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..17.
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FORMULA
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a(n) = (1/n)*Sum_{d|n} sigma(d)^d*moebius(n/d).
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MAPLE
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A158947 := proc(n) add(numtheory[sigma](d)^d*numtheory[mobius](n/d), d=numtheory[divisors](n))/n ; end: seq( A158947(n), n=1..40) ; [From R. J. Mathar, Apr 02 2009]
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MATHEMATICA
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f[n_] := Block[{d = Divisors@n}, Plus @@ (DivisorSigma[1, d]^d*MoebiusMu[n/d])/n]; Array[f, 17] [From Robert G. Wilson v, May 04 2009]
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CROSSREFS
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Sequence in context: A048164 A118909 A225157 * A000868 A000875 A094046
Adjacent sequences: A158944 A158945 A158946 * A158948 A158949 A158950
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.yu), Mar 31 2009
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EXTENSIONS
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Extended by R. J. Mathar, Apr 02 2009
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STATUS
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approved
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