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A230296
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a(n) = Sum_{i=1..n} d(72*i+1) - Sum_{i=1..n} d(18*i+1), where d(n) = A000005(n).
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8
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0, 2, 2, 3, 2, 2, 4, 2, 4, 6, 8, 8, 6, 4, 6, 5, 12, 8, 7, 8, 10, 12, 10, 16, 14, 12, 14, 12, 12, 12, 16, 18, 12, 14, 14, 12, 16, 20, 19, 19, 19, 26, 24, 22, 24, 24, 22, 20, 20, 20, 20, 26, 26, 24, 26, 28, 28, 22, 24, 24, 24, 30, 30, 32, 34, 36, 38, 33, 31, 30, 30, 36, 36, 35, 35, 36, 36, 36, 36, 36, 38, 38, 34, 34
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (2*log(2)/3) * n + O(n^(1/3)*log(n)). - Amiram Eldar, Apr 12 2024
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MAPLE
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MATHEMATICA
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Accumulate[Table[DivisorSigma[0, 72*n + 1] - DivisorSigma[0, 18*n + 1], {n, 1, 100}]] (* Amiram Eldar, Apr 12 2024 *)
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PROG
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(PARI) vector(100, n, sum(i=1, n, numdiv(72*i+1)) - sum(i=1, n, numdiv(18*i+1))) \\ Michel Marcus, Oct 09 2014
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CROSSREFS
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KEYWORD
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nonn,changed
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AUTHOR
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STATUS
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approved
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