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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

Thanks for the link
 
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
Adobbe forget us?

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
Adobbe forget us?

John[/QUOTE]Unfortunate, but true. PDF tries to recreate the represented document exactly, which means it's hard to resize something after it's initially printed.

Try the attached. I upsized the text. (I was reluctant to post the driver article because of the nature of the release I got, but since it is freely available on [noparse]ams.org[/noparse] now, I think this is a little more allowed...)

Be aware: without some more work some of the equations don't fit the page correctly, with the text overflowing off the right margin, but the main article text should be easier to manage.


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