Product of sigma(k)/phi(k)

Leroy Quet qq-quet at
Wed Jul 6 22:09:19 CEST 2005

Let sigma(k) = sum{j|k} j.
Let phi(k) be the number of positive integers <= k and coprime to k.

Then for which n's is

product{k=1 to n} sigma(k)/phi(k)

an integer?

This product seems to have fewer integer values than the product I wrote about earlier, product{k=1 to n} sigma(k)/d(k).
(d(k) is the number of positive divisors of k, of course.)

Leroy Quet

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