mersenneforum.org - View Single Post - Why 2^p-1 and not 2^p-2?

Blackadder · 2019-01-06, 20:02

Quote:

Originally Posted by ET_

Because 2^p-2 is even?

Is that rhetorical? I really should get back into my math books.

Quote:

Originally Posted by Batalov

In what sense special?
2^p-2 is special in its own way, too

Special as in: why are we calculating for 2^p-1 and not 2^p-2 as well. I guess the latter can't be prime?