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Expansion of phi_{8, 3}(x) where phi_{r, s}(x) = Sum_{n, m>0} m^r * n^s * x^{m*n}.
1

%I #29 Oct 31 2023 04:44:13

%S 0,1,264,6588,67648,390750,1739232,5765144,17318400,43224597,

%T 103158000,214360212,445665024,815732918,1521998016,2574261000,

%U 4433514496,6975762354,11411293608,16983569900,26433456000,37980768672,56591095968,78310997448

%N Expansion of phi_{8, 3}(x) where phi_{r, s}(x) = Sum_{n, m>0} m^r * n^s * x^{m*n}.

%C Multiplicative because A001160 is. - _Andrew Howroyd_, Jul 25 2018

%H Seiichi Manyama, <a href="/A282781/b282781.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = n^3*A001160(n) for n > 0.

%F a(n) = (6*A282752(n) - 2*A282780(n) - 6*A282102(n) + A008411(n) + A280869(n))/5184.

%F Sum_{k=1..n} a(k) ~ zeta(6) * n^9 / 9. - _Amiram Eldar_, Sep 06 2023

%F From _Amiram Eldar_, Oct 31 2023: (Start)

%F Multiplicative with a(p^e) = p^(3*e) * (p^(5*e+5)-1)/(p^5-1).

%F Dirichlet g.f.: zeta(s-3)*zeta(s-8). (End)

%t a[0]=0;a[n_]:=(n^3)*DivisorSigma[5,n];Table[a[n],{n,0,23}] (* _Indranil Ghosh_, Feb 21 2017 *)

%o (PARI) a(n) = if (n==0, 0, n^3*sigma(n, 5)); \\ _Michel Marcus_, Feb 21 2017

%Y Cf. A282211 (phi_{4, 3}), A282213 (phi_{6, 3}), this sequence (phi_{8, 3}).

%Y Cf. A282752 (E_2^2*E_4^2), A282780 (E_2^3*E_6), A282102 (E_2*E_4*E_6), A008411 (E_4^3), A280869 (E_6^2).

%Y Cf. A001160 (sigma_5(n)), A282050 (n*sigma_5(n)), A282751 (n^2*sigma_5(n)), this sequence (n^3*sigma_5(n)).

%Y Cf. A013664.

%K nonn,easy,mult

%O 0,3

%A _Seiichi Manyama_, Feb 21 2017