Product of sigma(k)/phi(k)
Leroy Quet
qq-quet at mindspring.com
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
seq.fan about earlier, product{k=1 to n} sigma(k)/d(k).
(d(k) is the number of positive divisors of k, of course.)
thanks,
Leroy Quet
More information about the SeqFan
mailing list