A301553 Expansion of Product_{k>=1} (1 + x^k)^(sigma_9(k)).

1, 1, 513, 20197, 413669, 12445003, 372981573, 9158438541, 223776496101, 5567873958982, 132009631562091, 3018411978731059, 68171158091244082, 1512439928316217508, 32796174722883608382, 698503712498547606328, 14656105328324700415778, 302787437988353941515934

Offset: 0

Author

Vaclav Kotesovec, Mar 23 2018

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..995

Crossrefs

Cf. A107742 (m=0), A192065 (m=1), A288414 (m=2), A288415 (m=3), A301548 (m=4), A301549 (m=5), A301550 (m=6), A301551 (m=7), A301552 (m=8).

Cf. A013957, A301547.

Programs

Mathematica

nmax = 30; CoefficientList[Series[Product[(1+x^k)^DivisorSigma[9, k], {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ exp(11 * Pi^(10/11) * (31*Zeta(11))^(1/11) * n^(10/11) / (2^(13/11) * 5^(10/11))) * (155*Zeta(11)/Pi)^(1/22) / (2^(155/264) * sqrt(11) * n^(6/11)).

G.f.: exp(Sum_{k>=1} sigma_10(k)*x^k/(k*(1 - x^(2*k)))). - Ilya Gutkovskiy, Oct 26 2018