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A301542 Expansion of Product_{k>=1} 1/(1 - x^k)^(sigma_4(k)). 9

%I #16 Oct 26 2018 14:32:08

%S 1,1,18,100,526,2546,12953,60929,282194,1265959,5580958,24057117,

%T 101922204,424244720,1739362261,7027590168,28017627428,110295521903,

%U 429110693519,1650961520518,6285554480496,23693047787961,88469251486817,327380976530282,1201122749057307

%N Expansion of Product_{k>=1} 1/(1 - x^k)^(sigma_4(k)).

%H Seiichi Manyama, <a href="/A301542/b301542.txt">Table of n, a(n) for n = 0..3315</a>

%F a(n) ~ exp(2^(3/2) * 3^(2/3) * Pi * (Zeta(5)/7)^(1/6) * n^(5/6)/5 + Pi * (7/Zeta(5))^(1/6) * n^(1/6) / (240 * sqrt(2) * 3^(2/3)) - 3*Zeta(5) / (8*Pi^4)) * Zeta(5)^(1/12) / (2^(3/4) * 3^(2/3) * 7^(1/12) * n^(7/12)).

%F G.f.: exp(Sum_{k>=1} sigma_5(k)*x^k/(k*(1 - x^k))). - _Ilya Gutkovskiy_, Oct 26 2018

%t nmax = 40; CoefficientList[Series[Product[1/(1-x^k)^DivisorSigma[4, k], {k, 1, nmax}], {x, 0, nmax}], x]

%Y Product_{k>=1} 1/(1 - x^k)^sigma_m(k): A006171 (m=0), A061256 (m=1), A275585 (m=2), A288391 (m=3), this sequence (m=4), A301543 (m=5), A301544 (m=6), A301545 (m=7), A301546 (m=8), A301547 (m=9).

%Y Cf. A001159, A301548.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, Mar 23 2018

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)