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A326755
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E.g.f.: Product_{k>=1} 1/(1 - x^(3*k-1)/(3*k-1)).
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6
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1, 0, 1, 0, 6, 24, 90, 504, 7560, 18144, 485352, 4626720, 32033232, 516559680, 9142044912, 64700161344, 1804378343040, 29722011830784, 308081755013760, 8202581858225664, 184073277074529024, 2067986628774743040, 75069447974837132544, 1673053361596502645760
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OFFSET
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0,5
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COMMENTS
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In the article by Lehmer, Theorem 7, p. 387, case b <> 0 and b <> 1, correct formula is W_n(S_a,b) ~ a^(-1/a) * exp(-gamma/a) * (Gamma((b-1)/a) / (Gamma(b/a) * Gamma(1/a))) * n^(1/a - 1).
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LINKS
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FORMULA
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a(n) ~ 3^(1/6) * exp(-gamma/3) * Gamma(1/3) * n! / (2*Pi*n^(2/3)).
a(n) ~ exp(-gamma/3) * n! / (3^(1/3) * Gamma(2/3) * n^(2/3)), where gamma is the Euler-Mascheroni constant A001620 and Gamma() is the Gamma function.
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MATHEMATICA
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nmax = 25; CoefficientList[Series[1/Product[(1-x^(3*k-1)/(3*k-1)), {k, 1, Floor[nmax/3] + 1}], {x, 0, nmax}], x] * Range[0, nmax]!
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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