I am sure this must have been discussed before with regards to OBD, but I could not find it.

I have just made a post in which I extended the table of trial factor depths found on

The Math page of mersenne.org all the way up to billion digit numbers.

Here's the post:

http://www.mersenneforum.org/showpos...1&postcount=70
I have included the methodology used to attain the numbers and I would appreciate any comments on it's validity.

If the numbers do turn out to be correct, then it looks like the OBD candidates need to be trial factored all the way to 87 bits, and currently there are 10 (soon to be 13) exponents at 81 bits.

In terms of levels, that's high enough to take the project to level 21.01, which at the minimum would require 22 candidates at 87 bits.