A generalized repunit PRP

For generalized repunit (probable) primes in bases 901, 903, 905:

(901^479-1)/900 is base 3-Fermat PRP! (1413 decimal digits)

(903^31-1)/902 is prime! (89 decimal digits, APRCL test)
(903^6719-1)/902 is base 3-Fermat PRP! (19857 decimal digits)

(905^223-1)/904 is base 3-Fermat PRP! (657 decimal digits)
(905^13241-1)/904 is base 3-Fermat PRP! (39147 decimal digits)
(905^61609-1)/904 is base 3-Fermat PRP! (182154 decimal digits)

See thread https://www.mersenneforum.org/showthread.php?t=29284

To be completed...