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 A160960 a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 12. 3
 1, 2047, 88573, 2096128, 12207031, 181308931, 329554457, 2146435072, 5230147077, 24987792457, 28531167061, 185660345344, 149346699503, 674597973479, 1081213356763, 2197949513728, 2141993519227, 10706111066619 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) is the number of lattices L in Z^11 such that the quotient group Z^11 / L is C_n. - Álvar Ibeas, Nov 26 2015 REFERENCES 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. LINKS Álvar Ibeas, Table of n, a(n) for n = 1..10000 FORMULA a(n) = J_11(n)/J_1(n) where J_11 and J_1(n) = A000010(n) are Jordan functions. - R. J. Mathar, Jul 12 2011 From Álvar Ibeas, Nov 26 2015: (Start) Multiplicative with a(p^e) = p^(10e-10) * (p^11-1) / (p-1). For squarefree n, a(n) = A000203(n^10). (End) MATHEMATICA b = 12; Table[Sum[MoebiusMu[n/d] d^(b - 1)/EulerPhi@ n, {d, Divisors@ n}], {n, 18}] (* Michael De Vlieger, Nov 27 2015 *) PROG (PARI) vector(100, n, sumdiv(n^10, d, if(ispower(d, 11), moebius(sqrtnint(d, 11))*sigma(n^10/d), 0))) \\ Altug Alkan, Nov 26 2015 CROSSREFS Sequence in context: A270697 A075954 A011561 * A038998 A068027 A075949 Adjacent sequences:  A160957 A160958 A160959 * A160961 A160962 A160963 KEYWORD nonn,mult AUTHOR N. J. A. Sloane, Nov 19 2009 EXTENSIONS Definition corrected by Enrique Pérez Herrero, Oct 30 2010 STATUS approved

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Last modified July 17 18:41 EDT 2019. Contains 325109 sequences. (Running on oeis4.)