Can you help to me

[Richard Guy]

Two questions (mainly for f.f):

How did you come to be interested in such numbers?

Is there any reason to expect that there are others?

R.

On Thu, 9 Oct 2003, Jud McCranie wrote:

> At 07:20 AM 10/9/2003, f.firoozbakht at sci.ui.ac.ir wrote:
> 
> >a(n) is the n-th odd number that sigma(n)=2n+6.
> >
> >a(1)=8925, a(2)=32445, a(3)=442365, a(4)=?
> >
> >I know a(4) is greater than 2*10^9 .
> 
> There are no terms between 2*10^9 and 6.5*10^9.
> 
>