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A110153
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G.f.: A(x) = Product_{n>=1} 1/(1 - 3^n*x^n)^(3/3^n).
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4
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1, 3, 12, 39, 138, 426, 1461, 4458, 14655, 45309, 145479, 443037, 1427196, 4329696, 13655325, 41795679, 131102229, 397649811, 1247247507, 3775785681, 11761535064, 35770717695, 110693177805, 335003030301, 1040296817955
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OFFSET
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0,2
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LINKS
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EXAMPLE
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A(x) = 1 + 3*x + 12*x^2 + 39*x^3 + 138*x^4 + 426*x^5 +... =
1/[(1-3*x)*(1-9*x^2)^(1/3)*(1-27*x^3)^(1/9)*(1-81*x^4)^(1/27)*...]
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PROG
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(PARI) a(n)=polcoeff(prod(k=1, n, 1/(1-3^k*x^k+x*O(x^n))^(3/3^k)), n)
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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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