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A160960
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a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 12.
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4
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1, 2047, 88573, 2096128, 12207031, 181308931, 329554457, 2146435072, 5230147077, 24987792457, 28531167061, 185660345344, 149346699503, 674597973479, 1081213356763, 2197949513728, 2141993519227, 10706111066619
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OFFSET
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1,2
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COMMENTS
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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
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LINKS
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FORMULA
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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
Multiplicative with a(p^e) = p^(10e-10) * (p^11-1) / (p-1).
For squarefree n, a(n) = A000203(n^10). (End)
Sum_{k=1..n} a(k) ~ c * n^11, where c = (1/11) * Product_{p prime} (1 + (p^10-1)/((p-1)*p^11)) = 0.1766326404... .
Sum_{k>=1} 1/a(k) = zeta(10)*zeta(11) * Product_{p prime} (1 - 2/p^11 + 1/p^21) = 1.0005003781952... . (End)
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MATHEMATICA
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b = 12; Table[Sum[MoebiusMu[n/d] d^(b - 1)/EulerPhi@ n, {d, Divisors@ n}], {n, 18}] (* Michael De Vlieger, Nov 27 2015 *)
f[p_, e_] := p^(10*e - 10) * (p^11-1) / (p-1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 25] (* Amiram Eldar, Nov 08 2022 *)
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PROG
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(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
(PARI) a(n) = {my(f = factor(n)); prod(i = 1, #f~, (f[i, 1]^11 - 1)*f[i, 1]^(10*f[i, 2] - 10)/(f[i, 1] - 1)); } \\ Amiram Eldar, Nov 08 2022
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CROSSREFS
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KEYWORD
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nonn,mult
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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