Nit: the largest prime discovered is
2^(277,232,917)-1
not
2^(277,232,917-1)
2^(277,232,917)-1
not
2^(277,232,917-1)
(2^77,232,917)-1
2 ⁷⁷ ²³² ⁹¹⁷ − 1
not
2 ⁷⁷ ²³² ⁹¹⁷ ⁻ ¹
There, no more ambiguity.
(Now I’m waiting for someone to jump on me to correct anything subtle.)
[Ah, I see, the parentheses were indeed a red herring. Ah well; let the superscripts remain.]