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A158275
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Denominators of antiharmonic means of divisors of n.
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3
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1, 3, 2, 1, 3, 6, 4, 3, 1, 9, 6, 2, 7, 12, 6, 1, 9, 3, 10, 1, 8, 18, 12, 6, 1, 21, 2, 4, 15, 18, 16, 3, 12, 27, 12, 1, 19, 6, 14, 9, 21, 24, 22, 2, 3, 36, 24, 2, 1, 1
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Antiharmonic mean of divisors of number n = Product (p_i^e_i) is sigma_2(n)/sigma_1(n) = A001157(n)/A000203(n) = Product ((p_i^(e_i+1)+1)/(p_i+1)).
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EXAMPLE
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Antiharmonic means of divisors of n>=1: 1, 5/3, 5/2, 3, 13/2, 25/6, ...
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MATHEMATICA
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Table[Denominator[DivisorSigma[2, n]/DivisorSigma[1, n]], {n, 50}] (* Ivan Neretin, May 22 2015 *)
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PROG
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(PARI) a(n) = denominator(sigma(n, 2)/sigma(n)); \\ Amiram Eldar, Nov 21 2022
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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