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A336978
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Expansion of Product_{k>=1} (1 - x^k * (1 + k*x)).
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6
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1, -1, -2, -2, 0, 3, 8, 11, 9, 8, -10, -31, -57, -58, -107, -85, -4, 120, 167, 383, 616, 905, 948, 479, -82, -125, -905, -3661, -5937, -8247, -8807, -7756, -6249, -8147, -3525, 8330, 30748, 54740, 82660, 85406, 86083, 109681, 148897, 148077, 81288, -57885, -257092, -490304
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OFFSET
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0,3
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LINKS
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FORMULA
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G.f.: exp( - Sum_{k>=1} x^k * Sum_{d|k} (1 + k/d * x)^d / d).
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MATHEMATICA
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m = 47; CoefficientList[Series[Product[1 - x^k*(1 + k*x), {k, 1, m}], {x, 0, m}], x] (* Amiram Eldar, May 01 2021 *)
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PROG
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(PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, 1-x^k*(1+k*x)))
(PARI) N=66; x='x+O('x^N); Vec(exp(-sum(k=1, N, x^k*sumdiv(k, d, (1+k/d*x)^d/d))))
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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