A _PDP_ or _Plateau and Depression Prime_ : 1999...9991
Also (18*10^28630-81)/9 or (10^28631-1)-8*(10^28632+1)
Ref.: file _deplat.htm_ at _www.worldofnumbers.com_ .
PRP to base 3,5,7.
PFGW Version 20041020.Win_Stable (v1.2 RC1c) [FFT v23.8]
Date of submission : 27 nov 2004

To be completed...