Side-effect PRPs from searching the FEP (First Encountered Prime) with 20000 ones.
These values n are smaller than 2144039 and are the failing numbers meaning
that with some smaller amount of ones appended at least one composite exists.

See ref.: 2144039*10^20000+R(20000),20007

PRP to base 3,5,7.
PFGW Version 3.7.10.64BIT.20150809.Win_Dev [GWNUM 28.6]
Date of submission : 10 march 2016.
http://www.worldofnumbers.com/em197.htm

To be completed...