The largest known Pell prime is equal to ((1 + √2)13,339 − (1 − √2)13,339) / 2√2, which is 5,106 digits long; it has been discovered on July 23, 2001.[1]

The largest known Pell probable prime is equal to ((1 + √2)90,197 − (1 − √2)90,197) / 2√2, which is 34,525 digits long; it has been discovered on September 13, 2004.[2]

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