The reason this PRP s form is so strange is that it is based on "mock-rational numbers" -- those that exhibit patterns in their digits. Its decimal expansion consists of repeating 518s and 407s, along with single repeating digits and other patterns separated by “random” strings.

Resuming input file MOCK5.txt at line 1
[N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 11
Running N-1 test using base 17
Running N+1 test using discriminant 23, base 1+sqrt(23)5185185185185185....000000000000000002969 is Fermat and Lucas PRP!

To be completed...