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-   -   Beginning driver/downdriver questions (https://www.mersenneforum.org/showthread.php?t=15981)

 biwema 2011-08-15 11:57

Beginning driver/downdriver questions

[QUOTE=Andi47;269120]There [I]is[/I] a need to worry - it killed the downdriver.[/QUOTE]

[Having a closer look into the factordb]

Oh. I see. My fault. :blush:
I always thought only a 2 * p could be dangerous. Now learned something.

At least there is still hope to get back the downdriver from 2^2 * p.

 henryzz 2011-08-15 19:40

Is it always possible to gain the downdriver within 3 iterations from any driver? Maybe 4 iterations?

 JohnFullspeed 2011-08-22 05:49

What???

[QUOTE=henryzz;269164]Is it always possible to gain the downdriver within 3 iterations from any driver? Maybe 4 iterations?[/QUOTE]

I dont know what you call a ''DRIVER" and a downdriver
Is someone can explain...

Merci
John

 firejuggler 2011-08-22 06:08

a driver is something you find from one iteration to another, like 2^2*7, 2*3 and make the sequence grow.
In some case, when the decomposition of the composite is 2* large integer, the sigma of the number is smaller than him., driving the sequence lower and lower, so it is a downdriver.

 schickel 2011-08-22 06:12

[QUOTE=JohnFullspeed;269763]I dont know what you call a ''DRIVER" and a downdriver
Is someone can explain...

Merci
John[/QUOTE]Drivers are defined in an article in [i]Mathematics of Computation[/i] in 1975 by Richard K Guy and John Selfridge. You can find the article free of charge [URL="http://www.ams.org/journals/mcom/1975-29-129/S0025-5718-1975-0384669-X/S0025-5718-1975-0384669-X.pdf"]here[/URL]. There is a later article clarifying the proof. That one is available [URL="http://www.ams.org/journals/mcom/1980-34-149/S0025-5718-1980-0551309-8/S0025-5718-1980-0551309-8.pdf"]here[/URL].

[SIZE="1"](Thanks to the American Mathematical Society who has made its older articles available free of change.)[/SIZE]

 JohnFullspeed 2011-08-22 11:01

Perhaps you have a option but where?

In a PDF file like [URL="http://www.ams.org/journals/mcom/1975-29-129/S0025-5718-1975-0384669-X/S0025-5718-1975-0384669-X.pdf"]here[/URL].you have a zoom (I read only size 26)
but when you print the doc the police is the original siize(10,12...)
Why?
PDF is well a Print Format

Like Millions of humans I am neer blind

John

 schickel 2011-08-22 20:41

1 Attachment(s)
[QUOTE=JohnFullspeed;269788]Perhaps you have a option but where?

In a PDF file like [URL="http://www.ams.org/journals/mcom/1975-29-129/S0025-5718-1975-0384669-X/S0025-5718-1975-0384669-X.pdf"]here[/URL].you have a zoom (I read only size 26)
but when you print the doc the police is the original siize(10,12...)
Why?
PDF is well a Print Format

Like Millions of humans I am neer blind