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A160957 a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 11. 2
1, 1023, 29524, 523776, 2441406, 30203052, 47079208, 268173312, 581120892, 2497558338, 2593742460, 15463962624, 11488207654, 48162029784, 72080070744, 137304735744, 125999618778, 594486672516, 340614792100, 1278749869056 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is the number of lattices L in Z^10 such that the quotient group Z^10 / 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

Index to Jordan function ratios J_k/J_1

FORMULA

a(n) = A069095(n)/A000010(n). - R. J. Mathar, Jul 12 2011

From Álvar Ibeas, Nov 26 2015: (Start)

Multiplicative with a(p^e) = p^(9e-9) * (p^10-1) / (p-1).

For squarefree n, a(n) = A000203(n^9).

(End)

MATHEMATICA

b = 11; Table[Sum[MoebiusMu[n/d] d^(b - 1)/EulerPhi@ n, {d, Divisors@ n}], {n, 20}] (* Michael De Vlieger, Nov 27 2015 *)

PROG

(PARI) vector(100, n, sumdiv(n^9, d, if(ispower(d, 10), moebius(sqrtnint(d, 10))*sigma(n^9/d), 0))) \\ Altug Alkan, Nov 26 2015

CROSSREFS

Sequence in context: A023060 A223079 A011560 * A038997 A068026 A075946

Adjacent sequences:  A160954 A160955 A160956 * A160958 A160959 A160960

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 25 14:01 EDT 2016. Contains 275034 sequences.