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A064167
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Product of numerator and denominator of the n-th harmonic number, 1 + 1/2 + 1/3 +...+ 1/n.
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3
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1, 6, 66, 300, 8220, 980, 50820, 213080, 17965080, 18600120, 2320468920, 2384502120, 412970037480, 422245703880, 430902992520, 1756076802480, 516336630329520, 58297387228080, 21362271268818480, 866533600973040, 97555876321904, 98772315738096, 52866073370045936, 481103506052529360
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OFFSET
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1,2
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COMMENTS
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Numerator and denominator in definition have no common divisors >1.
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LINKS
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EXAMPLE
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The 3rd harmonic number is 11/6. So a(3) = 11 * 6 = 66.
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MATHEMATICA
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Numerator[#]Denominator[#]&/@HarmonicNumber[Range[30]] (* Harvey P. Dale, May 01 2022 *)
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PROG
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(PARI) a(n) = my(h=sum(k=1, n, 1/k)); numerator(h) * denominator(h); \\ Michel Marcus, Sep 07 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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