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A280077
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Partial sums of A007429 (Sum_{d|n} sigma(d)).
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5
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1, 5, 10, 21, 28, 48, 57, 83, 101, 129, 142, 197, 212, 248, 283, 340, 359, 431, 452, 529, 574, 626, 651, 781, 819, 879, 937, 1036, 1067, 1207, 1240, 1360, 1425, 1501, 1564, 1762, 1801, 1885, 1960, 2142, 2185, 2365, 2410, 2553, 2679, 2779, 2828, 3113, 3179
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OFFSET
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1,2
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COMMENTS
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sigma(n) is the sum of the divisors of n (A000203).
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LINKS
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FORMULA
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G.f.: (1/(1-x)) * Sum_{k>=1} sigma(k) * x^k/(1 - x^k). - Seiichi Manyama, Jul 24 2022
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PROG
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(Magma) [&+[&+[SumOfDivisors(d): d in Divisors(k)]: k in [1..n]]: n in [1..100]]
(PARI) a(n) = sum(k=1, n, sumdiv(k, d, sigma(d))); \\ Michel Marcus, May 29 2018
(PARI) my(N=50, x='x+O('x^N)); Vec(sum(k=1, N, sigma(k)*x^k/(1-x^k))/(1-x)) \\ Seiichi Manyama, Jul 24 2022
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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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