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0, 1, 2, 0, 0, -5, 0, -7, 0, 0, 0, 0, 12, 0, 0, 15, 0, 0, 0, 0, 0, 0, -22, 0, 0, 0, -26, 0, 0, 0, 0, 0, 0, 0, 0, 35, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -51, 0, 0, 0, 0, 0, -57, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 70, 0, 0, 0, 0, 0, 0, 77, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -92, 0, 0, 0, 0, 0, 0, 0, -100, 0, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Convolved with the partition numbers A000041 = sigma(n) prefaced with a 0 gives (0, 1, 3, 4, 7, 6, 12, 8, 15, 13,...).
Triangle A174740 convolves the partition numbers with a variant of A147843, having row sums = A000203, sigma(n). [Gary W. Adamson, Mar 28 2010]
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FORMULA
| G.f.: deriv(-eta(x)) where eta(x) = prod(n>=1, 1-x^n). - Joerg Arndt, Mar 14 2010
a(n) = Sum_{k=0..n-1} A010815(k)*sigma(n-k), where sigma(n) = A000203(n) is the number of divisors of n. [From Paul D. Hanna, Jul 2 2011]
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EXAMPLE
| a(5) = -5 = (-5) * A010815(5) = (-5) * 1.
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CROSSREFS
| Cf. A010815, A000203, A000041, A001318
Cf. A174740 [From Gary W. Adamson, Mar 28 2010]
Sequence in context: A159814 A169774 A057611 * A094597 A202992 A158830
Adjacent sequences: A147840 A147841 A147842 * A147844 A147845 A147846
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KEYWORD
| sign,easy
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AUTHOR
| Gary W. Adamson (qntmpkt(AT)yahoo.com), Nov 15 2008
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