mersenneforum.org  

Go Back   mersenneforum.org > Factoring Projects > Cunningham Tables

Reply
 
Thread Tools
Old 2007-12-20, 16:49   #1
R.D. Silverman
 
R.D. Silverman's Avatar
 
Nov 2003

22×5×373 Posts
Default Reciprocal Sextic

Would someone with access to a CA package please find
the coefficients of the reciprocal sextic for 2,1694M?

The 2^1694M/2^242M is

2^726 - 2^666 + 2^605 - 2^484 + 2^424 - 2^363 + 2^303 - 2^242 +
2^121 - 2^61 + 1

This should be expressible as a sextic polynomial in (2x + 1/x) with x = 2^61.

Doing it by hand is a mess.
R.D. Silverman is offline   Reply With Quote
Old 2007-12-20, 17:07   #2
fivemack
(loop (#_fork))
 
fivemack's Avatar
 
Feb 2006
Cambridge, England

2·132·19 Posts
Default

Don't you mean x=2^60 here?

Code:
% gp
a = factor(2^14*x^28+1)[3,1]
u = 2*x + 1/x
(x^6 * (u^6-2*u^5-10*u^4+20*u^3+16*u^2-32*u+8)) - a
so I reckon the sextic is
u^6-2*u^5-10*u^4+20*u^3+16*u^2-32*u+8

with u = 2x+1/x, x=2^60

Tom
fivemack is offline   Reply With Quote
Old 2007-12-20, 17:31   #3
R. Gerbicz
 
R. Gerbicz's Avatar
 
"Robert Gerbicz"
Oct 2005
Hungary

148610 Posts
Default

Quote:
Originally Posted by fivemack View Post
Don't you mean x=2^60 here?

so I reckon the sextic is
u^6-2*u^5-10*u^4+20*u^3+16*u^2-32*u+8

with u = 2x+1/x, x=2^60

Tom
You're right. I've checked your polynom, it's good with u=2x+1/x, x=2^60.
R. Gerbicz is offline   Reply With Quote
Old 2007-12-20, 18:02   #4
fivemack
(loop (#_fork))
 
fivemack's Avatar
 
Feb 2006
Cambridge, England

642210 Posts
Default

Quote:
Originally Posted by R.D. Silverman View Post
Would someone with access to a CA package please find
the coefficients of the reciprocal sextic for 2,1694M?
For calculations that take less than 20 seconds, magma, which is the superpower of number-theoretical computer algebra packages, is available at http://magma.maths.usyd.edu.au/calc/
fivemack is offline   Reply With Quote
Old 2007-12-20, 19:04   #5
R.D. Silverman
 
R.D. Silverman's Avatar
 
Nov 2003

164448 Posts
Default

Quote:
Originally Posted by fivemack View Post
For calculations that take less than 20 seconds, magma, which is the superpower of number-theoretical computer algebra packages, is available at http://magma.maths.usyd.edu.au/calc/

I am not allowed to download any software over the net owing to
security considerations.
R.D. Silverman is offline   Reply With Quote
Old 2007-12-20, 21:16   #6
Wacky
 
Wacky's Avatar
 
Jun 2003
The Texas Hill Country

100010000012 Posts
Default

Quote:
Originally Posted by R.D. Silverman View Post
I am not allowed to download any software over the net owing to security considerations.
Bob,

AFAICT, this is a website address that allows you to run a "simple" magma calculation on THEIR server and returns the result to you.

Nothing is "downloaded". It is a simple submit/response system.
Wacky is offline   Reply With Quote
Old 2007-12-21, 14:14   #7
R.D. Silverman
 
R.D. Silverman's Avatar
 
Nov 2003

22·5·373 Posts
Default

Quote:
Originally Posted by Wacky View Post
Bob,

AFAICT, this is a website address that allows you to run a "simple" magma calculation on THEIR server and returns the result to you.

Nothing is "downloaded". It is a simple submit/response system.
Thanks for the heads up.
R.D. Silverman is offline   Reply With Quote
Old 2007-12-21, 15:48   #8
xilman
Bamboozled!
 
xilman's Avatar
 
"π’‰Ίπ’ŒŒπ’‡·π’†·π’€­"
May 2003
Down not across

47×229 Posts
Default

Quote:
Originally Posted by R.D. Silverman View Post
Thanks for the heads up.
Quote:
Originally Posted by A very handsome gentleman
re: bob's post about getting some weird thing done but he cannot download programs at work, and that he doesn't want to do it by hand because it is too messy:

Wouldn't it be more satisfying to write the program yourself? If we make things too easy then there is no sense of accomplishment.



or something to that effect

who takes the challenge?

OK, I'm game.



Paul

Last fiddled with by xilman on 2007-12-21 at 16:10 Reason: Boy, am I going to get into trouble for this one!
xilman is offline   Reply With Quote
Old 2007-12-21, 16:03   #9
R.D. Silverman
 
R.D. Silverman's Avatar
 
Nov 2003

22×5×373 Posts
Default

Quote:
Originally Posted by xilman View Post
OK, I'm game.



re: bob's post about getting some weird thing done but he cannot download programs at work, and that he doesn't want to do it by hand because it is too messy:

Wouldn't it be more satisfying to write the program yourself? If we make things too easy then there is no sense of accomplishment.


Paul
I already know how to solve the problem. I know how to write the code.
Writing such code would not give me a sense of accomplishment. I
would learn nothing in the process.

It is an easy, but *tedious* exercize in junior high school algebra.
I just don't have the time to write such a program. My time is better
spent on developing new ideas.

I don't ask others to solve any of my problems unless I already know how
to do it myself.
R.D. Silverman is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sum of reciprocal of squares of all prime numbers Damian Math 3 2010-05-24 23:57
Prime Reciprocal Sums davar55 Puzzles 3 2009-12-24 19:45

All times are UTC. The time now is 08:14.


Tue Jul 27 08:14:13 UTC 2021 up 4 days, 2:43, 0 users, load averages: 2.30, 1.90, 1.78

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.