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.