A _PDP_ or _Plateau and Depression Prime_ : 1999...9991
Also (18*10^23672-81)/9 or (10^23673-1)-8*(10^23672+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 : 26 nov 2004

To be completed...