Useless p-1 work
 

[QUOTE]
77900201,825000,22893750
77900461,825000,22893750
77900497,825000,22893750
77909939,825000,22893750
79279351,825000,15881250
79299397,780000,11700000
79299421,725000,7612500
79299433,660000,3465000
79299719,780000,12480000
79299821,1110000,1110000
79299907,1110000,1110000
79299959,740000,16465000
[/QUOTE]

What a waste of cpu cycles!
all b1's are smaller than m so they assume that the largest factor of p-1 is m and they don't reach it.

what a waste!

Joss

[QUOTE=jocelynl]What a waste of cpu cycles!
all b1's are smaller than m so they assume that the largest factor of p-1 is m and they don't reach it.

what a waste!

Joss[/QUOTE]Be careful! George's code includes an additional m over and above the ones implied by the b1 limit. I asked him this very question some time ago.

Paul

So I see!

I tested 2^251-1
b1=2 b2=2 and found the factor 27271151

Tks xilman
You're right, b1 is actually b1+m
There was no wasted cycle.
I pushed the :nuke: too early.

Joss

[quote]b1 is actually b1+m[/quote]No. Prime95 enforces minimum values on b1 and b2, so b1 = b2 = 2 got bumped up. The minimum used to be 30; maybe now it's 60 or more.

27271151 - 1 = 2 [color=green]×[/color] 5^2 [color=green]×[/color] 41 [color=green]×[/color] 53 [color=green]×[/color] 251

Pminus1=79299433,660000,3465000,0,0

This will find any factor of 2^79299433-1 where

factor = 2 * k * 79299433 + 1

and

k has largest factor =< 3465000 and all other factors =< 660000.

Actually, there are stage 2 extensions such that some k with largest factor =< (3465000 * a small integer) will be found, in certain cases.