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A160891
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Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 5.
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8
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1, 15, 40, 120, 156, 600, 400, 960, 1080, 2340, 1464, 4800, 2380, 6000, 6240, 7680, 5220, 16200, 7240, 18720, 16000, 21960, 12720, 38400, 19500, 35700, 29160, 48000, 25260, 93600, 30784, 61440, 58560, 78300, 62400, 129600, 52060, 108600, 95200
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OFFSET
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1,2
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REFERENCES
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J. H. Kwak and J. Lee, Enumeration of graph coverings, surface branched coverings and related group theory, in Combinatorial and Computational Mathematics (Pohang, 2000), ed. S. Hong et al., World Scientific, Singapore 2001, pp. 97-161. See p. 134.
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LINKS
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Enrique Pérez Herrero, Table of n, a(n) for n = 1..5000
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FORMULA
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a(n)=J_4(n)/J_1(n)=J_4(n)/phi(n)=A059377(n)/A000010(n), where J_k is the k-th Jordan Totient Function [From Enrique Pérez Herrero, Oct 19 2010]
Multiplicative with a(p^e) = p^(3e-3)*(1+p+p^2+p^3). - R. J. Mathar, Jul 10 2011
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MAPLE
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A160891 := proc(n) a := 1 ; for f in ifactors(n)[2] do p := op(1, f) ; e := op(2, f) ; a := a*p^(3*e-3)*(1+p+p^2+p^3) ; end do; a; end proc:
seq(A160891(n), n=1..20) ; # R. J. Mathar, Jul 10 2011
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MATHEMATICA
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A160891[n_]:=DivisorSum[n, MoebiusMu[n/#]*#^(5-1)/EulerPhi[n]&] [From Enrique Pérez Herrero, Oct 19 2010]
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CROSSREFS
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Cf. A160893, A160895, A160897, A160960, A160972, A161010, A161025, A161139 , A161167, A161213, A065958, A065959, A065960 [From Enrique Pérez Herrero, Oct 19 2010]
Sequence in context: A044473 A067724 A005337 * A223425 A175926 A038991
Adjacent sequences: A160888 A160889 A160890 * A160892 A160893 A160894
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KEYWORD
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nonn,mult
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AUTHOR
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N. J. A. Sloane, Nov 19 2009
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EXTENSIONS
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Definition corrected by Enrique Pérez Herrero, Aug 22 2010
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STATUS
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approved
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