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A294403
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E.g.f.: exp(-Sum_{n>=1} sigma(n) * x^n).
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4
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1, -1, -5, -7, 1, 839, 4171, 54305, 102817, -4303441, -74521349, -1595325271, -20768141855, -222701825737, 1485790534411, 65580347824529, 2880129557707201, 67631429234674655, 1543424936566399867, 23542870556917468889, 119940955037901088321
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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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a(0) = 1 and a(n) = (-1) * (n-1)! * Sum_{k=1..n} k*A000203(k)*a(n-k)/(n-k)! for n > 0.
E.g.f.: Product_{k>=1} (1 - x^k)^f(k), where f(k) = (1/k) * Sum_{j=1..k} gcd(k,j)^2. - Ilya Gutkovskiy, Aug 17 2021
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PROG
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(PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(-sum(k=1, N, sigma(k)*x^k))))
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CROSSREFS
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E.g.f.: exp(-Sum_{n>=1} sigma_k(n) * x^n): A294402 (k=0), this sequence (k=1), A294404 (k=2).
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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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