3XyQWnaYY7oHngexisi4Po1kfgce found a megaprime for base R198.
The prime 3342*198^466948-1 has 1.072.427 digits and entered the T5k PrimePages.

SkyHighWeFly, a member of the team Antarctic Crunchers found a megaprime for base R198.
The prime 484*198^491623-1 has 1.129.097 digits and entered the T5k PrimePages.

Source