Question on "ECM on Mersenne cofactor" work type
I set Prime95 up to do the "ECM on Mersenne cofactor" work type and was sort of expecting that I would get an assignment that ran ECM on a cofactor of a Mersenne number many times, until it was deemed unproductive to continue. What actually happens is that I get an assignment to do ECM on a Mersenne number once, then it moves on to a different Mersenne number.
Using M2106347 as an example (approx 700000 decimal digits if my maths is correct), it has 4 known factors totalling about 50 decimal digits, so the remaining unfactored amount is relatively speaking a similar size to M2106347. Is this why we just repeat the ECM on M2106347 instead of on the unfactored amount?
I still don't understand the apparent scatter gun approach where I get assigned 1 attempt at many different exponents (rather than repeatedly trying to factor the same number).
