April 1 comes late this year

Richard Guy rkg at cpsc.ucalgary.ca
Wed Nov 23 19:55:32 CET 2005

When I tried  1, 2, 18, 26  on OEIS I got
no hits, but  1, 3, 8, 9  yielded my full
quota of  30.

Alas, I fear that they are both finite
in the present context, so won't make it
into the Hall of Fame when Neil returns
from his well-earned rest (though I don't
believe that he ever takes one).

They are the integer values of

$\prod_{i=1}^n \frac{\sigma n}{n}$

and the values of  n  which make this
an integer, where  \sigma n  is the
sum of divisors function.  How did
I come to be thinking about this?  Did
someone mention it recently?

Season's greetings    R.

More information about the SeqFan mailing list