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 A160956 a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 9. 1

%I

%S 511,130305,1676080,16679040,49902216,427400400,490968800,2134917120,

%T 3665586960,12725065080,10953738768,54707251200,34736533160,

%U 125197044000,163679268480,273269391360,222788253240,934724674800

%N a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 9.

%H G. C. Greubel, <a href="/A160956/b160956.txt">Table of n, a(n) for n = 1..5000</a>

%H J. H. Kwak and J. Lee, <a href="https://doi.org/10.1142/9789812799890_0005">Enumeration of graph coverings, surface branched coverings and related group theory</a>, in Combinatorial and Computational Mathematics (Pohang, 2000), ed. S. Hong et al., World Scientific, Singapore 2001, pp. 97-161. See p. 134.

%F a(n) = 511*A160908(n). - _R. J. Mathar_, Mar 16 2016

%t A160956[n_] := DivisorSum[n, MoebiusMu[n/#]*#^(9 - 1)/EulerPhi[n] &]; Table[511*A160956[n], {n, 1, 50}] (* _G. C. Greubel_, Dec 12 2017 *)

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Nov 19 2009

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Last modified February 22 18:03 EST 2020. Contains 332148 sequences. (Running on oeis4.)