Found with PFGW Version 3.6.0

84^19381-83 is 2-PRP! (21.3485s+0.0023s)
84^19381-83 is 3-PRP! (21.4980s+0.0024s)
84^19381-83 is 5-PRP! (21.2305s+0.0024s)
84^19381-83 is 7-PRP! (21.3260s+0.0025s)
84^19381-83 is 11-PRP! (21.2709s+0.0022s)

Primality testing 84^19381-83 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 2
Running N+1 test using discriminant 59, base 1+sqrt(59)
Calling N-1 BLS with factored part 0.53% and helper 0.00% (1.59% proof)
84^19381-83 is Fermat and Lucas PRP! (161.9817s+0.0030s)

To be completed...