This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A160956 #18 Nov 09 2022 07:55:45
%S A160956 511,130305,1676080,16679040,49902216,427400400,490968800,2134917120,
%T A160956 3665586960,12725065080,10953738768,54707251200,34736533160,
%U A160956 125197044000,163679268480,273269391360,222788253240,934724674800,482144484080,1628808330240,1610377664000
%N A160956 a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 9.
%H A160956 Amiram Eldar, <a href="/A160956/b160956.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..5000 from G. C. Greubel)
%H A160956 Jin Ho Kwak and Jaeun 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 A160956 a(n) = 511*A160908(n). - _R. J. Mathar_, Mar 16 2016
%F A160956 From _Amiram Eldar_, Nov 08 2022: (Start)
%F A160956 Sum_{k=1..n} a(k) ~ c * n^8, where c = (511/8) * Product_{p prime} (1 + (p^7-1)/((p-1)*p^8)) = 123.8157549... .
%F A160956 Sum_{k>=1} 1/a(k) = (zeta(7)*zeta(8)/511) * Product_{p prime} (1 - 2/p^8 + 1/p^15) = 0.001965303453... . (End)
%t A160956 A160956[n_] := DivisorSum[n, MoebiusMu[n/#]*#^(9 - 1)/EulerPhi[n] &]; Table[511*A160956[n], {n, 1, 50}] (* _G. C. Greubel_, Dec 12 2017 *)
%t A160956 f[p_, e_] := p^(7*e - 7) * (p^8-1) / (p-1); a[1] = 511; a[n_] := 511 * Times @@ f @@@ FactorInteger[n]; Array[a, 20] (* _Amiram Eldar_, Nov 08 2022 *)
%o A160956 (PARI) a(n) = {my(f = factor(n)); 511 * prod(i = 1, #f~, (f[i,1]^8 - 1)*f[i,1]^(7*f[i,2] - 7)/(f[i,1] - 1));} \\ _Amiram Eldar_, Nov 08 2022
%Y A160956 Cf. A000010, A013665, A013666, A160908.
%K A160956 nonn
%O A160956 1,1
%A A160956 _N. J. A. Sloane_, Nov 19 2009