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A282920
Expansion of Product_{k>=1} (1 - x^(7*k))^8/(1 - x^k)^9 in powers of x.
2
1, 9, 54, 255, 1035, 3753, 12483, 38701, 113193, 315013, 839802, 2155905, 5352252, 12894426, 30233558, 69160869, 154677325, 338822547, 728084435, 1536931932, 3190959918, 6523084815, 13142291319, 26118847655, 51244059231, 99322878506, 190306301025
OFFSET
0,2
LINKS
FORMULA
G.f.: Product_{n>=1} (1 - x^(7*n))^8/(1 - x^n)^9.
a(n) ~ exp(Pi*sqrt(110*n/21)) * sqrt(55) / (4*sqrt(3) * 7^(9/2) * n). - Vaclav Kotesovec, Nov 10 2017
MATHEMATICA
nmax = 30; CoefficientList[Series[Product[(1 - x^(7*k))^8 /(1 - x^k)^9, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 10 2017 *)
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(prod(j=1, N, (1 - x^(7*j))^8/(1 - x^j)^9)) \\ G. C. Greubel, Nov 18 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!( (&*[(1 - x^(7*j))^8/(1 - x^j)^9: j in [1..m+2]]) )); // G. C. Greubel, Nov 18 2018
(Sage)
R = PowerSeriesRing(ZZ, 'x')
prec = 30
x = R.gen().O(prec)
s = prod((1 - x^(7*j))^8/(1 - x^j)^9 for j in (1..prec))
print(s.coefficients()) # G. C. Greubel, Nov 18 2018
CROSSREFS
Cf. A282919.
Sequence in context: A289254 A059597 A327387 * A023008 A079817 A169796
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 24 2017
STATUS
approved