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A104529
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Denominator of Sum_{k=1..n} 1/tau(k), where tau(k) is the number of divisors function.
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5
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1, 2, 1, 3, 6, 12, 12, 6, 6, 12, 12, 12, 12, 6, 12, 60, 60, 20, 20, 60, 15, 60, 60, 120, 40, 40, 40, 120, 120, 30, 15, 30, 60, 15, 60, 180, 180, 45, 180, 360, 360, 45, 90, 45, 90, 180, 180, 180, 180, 180, 90, 45, 90, 360, 360, 45, 180, 90, 45, 180, 180, 90, 45, 315, 1260
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OFFSET
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1,2
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LINKS
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EXAMPLE
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1,3/2,2,7/3,17/6
a(4)=3 because 1/tau(1)+1/tau(2)+1/tau(3)+1/tau(4)=1/1+1/2+1/2+1/3=7/3.
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MAPLE
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with(numtheory): a:=n->denom(sum(1/tau(k), k=1..n)): seq(a(n), n=1..70);
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MATHEMATICA
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Denominator[Accumulate[1/#&/@DivisorSigma[0, Range[70]]]] (* Harvey P. Dale, Dec 18 2012 *)
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CROSSREFS
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KEYWORD
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frac,nonn
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AUTHOR
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STATUS
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approved
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