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A062731
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Sum of divisors of 2*n.
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31
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3, 7, 12, 15, 18, 28, 24, 31, 39, 42, 36, 60, 42, 56, 72, 63, 54, 91, 60, 90, 96, 84, 72, 124, 93, 98, 120, 120, 90, 168, 96, 127, 144, 126, 144, 195, 114, 140, 168, 186, 126, 224, 132, 180, 234, 168, 144, 252, 171, 217, 216, 210, 162, 280, 216, 248, 240, 210
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OFFSET
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1,1
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COMMENTS
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a(n) is also the total number of parts in all partitions of 2*n into equal parts. - Omar E. Pol, Feb 14 2021
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LINKS
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FORMULA
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Dirichlet g.f.: zeta(s) * zeta(s-1) * (3 - 2^(1-s)).
Sum_{k=1..n} a(k) ~ 5 * Pi^2 * n^2 / 24. (End)
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MATHEMATICA
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PROG
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(PARI) vector(66, n, sigma(2*n, 1))
(PARI) for (n=1, 1000, write("b062731.txt", n, " ", sigma(2*n)) ) \\ Harry J. Smith, Aug 09 2009
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CROSSREFS
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Cf. A008438, A074400, A182818, A239052 (odd bisection), A326124 (partial sums), A054784, A215947, A336923, A346870, A346878, A346880, A355750.
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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Zero removed and offset corrected by Omar E. Pol, Jul 17 2009
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STATUS
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approved
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