Mersenne Digest Sunday, December 19 1999 Volume 01 : Number 672
----------------------------------------------------------------------
Date: Fri, 17 Dec 1999 00:33:15 EST
From: [EMAIL PROTECTED]
Subject: Mersenne: Re: Mersenne Digest V1 #671
<< "The Acceleration of Just About Everything" >>
Until we hit the End of Moore's Law (cue ominous music) in 2020 and
everything falls apart.
The only constant in life is change? | dlife/dt | > 0 for all t.
Sheesh, the list is awfully quiet.
Anyone miss seeing my Mersenne primes paper back during Thanksgiving?
http://homepages.go.com/~joekorovin/Mersenne.html or
http://homepages.go.com/~joekorovin/Mersenne.zip will do the trick. Feel free
to link to these URLs and attach my real name Stephan Lavavej, just not
STL137. The paper was physically submitted to the program I wrote it for
today. I get results on it in July.
Unrelated, but cool, poem (not by me):
Nature and nature's laws lay hidden from sight.
God said, "Let Newton be!", and all was light.
It did not last; the devil, saying "Ho!
Let Einstein be!", restored the status quo.
Everyone must be busy searching for the Missing Mersenne, or something.
Stephan "Ahoy hoy, lowly mortals" Lavavej
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Date: Fri, 17 Dec 1999 18:06:50 +0000
From: Tony Forbes <[EMAIL PROTECTED]>
Subject: Mersenne: MM61
MM61.
Thanks to all who joined in the search for a factor of 2^(2^61-1)-1.
Keep up the good work! There is now a 'progress' page at
http://www.ltkz.demon.co.uk/ar2/mm61.htm
- --
Tony
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Date: Fri, 17 Dec 1999 13:03:27 -0600
From: "Griffith, Shaun" <[EMAIL PROTECTED]>
Subject: Mersenne: RE: Fibonacci Series
Ian McLoughlin wrote:
> Since the list is quiet...
> Does a Fibonnacci series contain a finite or an infinite number of primes?
> From what I understand..
> In a gen.F sequence if the first two numbers are divisible by a prime all
> its numbers are divisible by the same prime, if the first two numbers are
> co-prime is there a generalised sequence that contains NO PRIMES....
The generalized Fibonacci sequence seems to generate at least one prime
regardless of the values assigned to Fib(1), Fib(2), *unless* Fib(1) and
Fib(2) are even. Then there is never an odd number, and never a chance for a
prime after Fib(2) (though Fib(1) or Fib(2) may be =2, but that seems
trivial).
I tried it with composite odd numbers, such as 15,77, which happen to be
coprime. The first 3 primes generated are Fib(7)=691, Fib(14)=20101, and
Fib(28)=16945081.
- -Shaun
Quantum Mechanics: The dreams stuff is made of
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Date: Fri, 17 Dec 1999 17:48:25 -0500
From: "Vincent J. Mooney Jr." <[EMAIL PROTECTED]>
Subject: Mersenne: Zip Codes
Also since the list is quite quiet, my old zip code of 21701 is a Mersenne
prime.
Are there any other zip codes that are Mersenne primes?
I don't know how to look up 02203 or 02281 for example.
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Date: Fri, 17 Dec 1999 18:29:18 -0500
From: "Rick Pali" <[EMAIL PROTECTED]>
Subject: RE: Mersenne: Zip Codes
> Are there any other zip codes that are Mersenne primes?
Our postal codes have some letters so that's not going to work. The sixteen
digit number on my bank-machine code is prime, however.
Rick.
- -+---
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Date: Fri, 17 Dec 1999 16:35:32 -0900 (AKST)
From: Gordon Bower <[EMAIL PROTECTED]>
Subject: Mersenne: v19 and priorities
I recently decided to start switching over from v18 to v19 (yes, I know I
could have months ago, but I thought I'd give the rest of you time to find
all the bugs first.) I did notice a performance improvement -- about 8% on
a 350 doing LL tests, about 2% on an old P-120 doing double-checks. As the
opportunity arises I will probably switch over the other 5 machines I also
am allowed to run the program on.
Something strange happened, though. Version 19 slows down considerably
more in response to my doing other low-demand things on my machine,
reading email/web browsing/etc. Is this just in the nature of v19,
something to do with the optimizations that were added to speed it up? (It
does still average a faster rate in the long run).
I did not change any of the priority settings in prime.ini when switching
versions.
As long as I am writing to the list -- perhaps someone could explain in a
little more detail than readme.txt does as to what the valid range of
values for the Priority variable are and what the effect of each is on NT
and 95? I experimented a little by trial and error last summer when a
friend running a 3-D screen saver offered to let me run the program on his
machine, but we never had much success fine-tuning it so as to not
interfere with his work.
GRB
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Date: Sat, 18 Dec 1999 03:08:22 +0100 (CET)
From: Henrik Olsen <[EMAIL PROTECTED]>
Subject: Re: Mersenne: RE: Fibonacci Series
On Fri, 17 Dec 1999, Griffith, Shaun wrote:
> Ian McLoughlin wrote:
> > Since the list is quiet...
> > Does a Fibonnacci series contain a finite or an infinite number of primes?
> > From what I understand..
> > In a gen.F sequence if the first two numbers are divisible by a prime all
> > its numbers are divisible by the same prime, if the first two numbers are
> > co-prime is there a generalised sequence that contains NO PRIMES....
>
> The generalized Fibonacci sequence seems to generate at least one prime
> regardless of the values assigned to Fib(1), Fib(2), *unless* Fib(1) and
> Fib(2) are even. Then there is never an odd number, and never a chance for a
If they are both even they aren't coprime. :)
> prime after Fib(2) (though Fib(1) or Fib(2) may be =2, but that seems
> trivial).
>
> I tried it with composite odd numbers, such as 15,77, which happen to be
> coprime. The first 3 primes generated are Fib(7)=691, Fib(14)=20101, and
> Fib(28)=16945081.
>
> -Shaun
> Quantum Mechanics: The dreams stuff is made of
>
> _________________________________________________________________
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> Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
>
- --
Henrik Olsen, Dawn Solutions I/S URL=http://www.iaeste.dk/~henrik/
Thomas Covenant: I am the savior of The Land. Linden Avery: Can I help?
Thomas Covenant: Over my dead body.(dies) (Linden Avery saves The Land.)
The Second Chronicles of Thomas Covenant, Book-A-Minute version
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Date: Fri, 17 Dec 1999 22:53:29 -0500
From: "Vincent J. Mooney Jr." <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Zip Codes
Thanks, Joth.
1. 00002 Not good
2. 00003 Not good
3. 00005 Not good
4. 00007 Not good
5. 00013 Not good
6. 00017 Not good
7. 00019 Not good
8. 00031 Not good
9. 00061 Not good
10. 00089 Not good
11. 00107 Not good
12. 00127 Not good
13. 00521 Not good
14. 00607 Not good
15. 01279 Not good
16. 02203 A valid zip code
17. 02281 Not good
18. 03217 A valid zip code
19. 04253 A valid zip code
20. 04423 A valid zip code
21. 09689 Not good
22. 09941 Not good
23. 11213 A valid zip code
24. 19937 Not good
25. 21701 A valid zip code
26. 23209 Not good
27. 44497 Not good
28. 86243 Not good
29 and higher are 6 digits.
At 06:13 PM 12/17/99 -0800, Joth Tupper wrote:
>You might check www.usps.com.
>
>----- Original Message -----
>From: Vincent J. Mooney Jr. <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Friday, December 17, 1999 2:48 PM
>Subject: Mersenne: Zip Codes
>
>
>> Also since the list is quite quiet, my old zip code of 21701 is a Mersenne
>> prime.
>>
>> Are there any other zip codes that are Mersenne primes?
>>
>> I don't know how to look up 02203 or 02281 for example.
>>
>> _________________________________________________________________
>> Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
>> Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
>>
>
>
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------------------------------
Date: Sat, 18 Dec 1999 15:45:25 +1100
From: Simon Burge <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Zip Codes
"Vincent J. Mooney Jr." wrote:
> Also since the list is quite quiet, my old zip code of 21701 is a Mersenne
> prime.
>
> Are there any other zip codes that are Mersenne primes?
>
> I don't know how to look up 02203 or 02281 for example.
In Australia, we have 4 digit post codes (not zip codes). Here's a
list:
1279 Sydney, NSW (mail center, not residential)
2203 Dulwich Hill, NSW
2281 Blacksmiths, NSW
Cams Wharf, NSW
Catherine Hill Bay, NSW
Caves Beach, NSW
Little Pelican, NSW
Middle Camp, NSW
Nords Wharf, NSW
Pelican, NSW
Swansea, NSW
Swansea Heads, NSW
3217 Deakin University, Vic
4253 <not valid>
4423 Glenmorgan, Qld
9689 <not valid>
9941 <not valid>
Unfortunately(?!) I live in Wandana Heights (3216) but am only about
a kilometre or two as the crow flies from Deakin University. Little
Pelican sounds like pick of the bunch as a place name though :)
'Tis quiet on the list, isn't it...
Simon.
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------------------------------
Date: Sat, 18 Dec 1999 00:06:10 -0800 (PST)
From: poke <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Zip Codes
Is there anything geographically special about your old town?
On Fri, 17 Dec 1999, Vincent J. Mooney Jr. wrote:
> Also since the list is quite quiet, my old zip code of 21701 is a Mersenne
> prime.
>
> Are there any other zip codes that are Mersenne primes?
>
> I don't know how to look up 02203 or 02281 for example.
>
> _________________________________________________________________
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> Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
>
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------------------------------
Date: Sat, 18 Dec 1999 08:34:06 -0000
From: "Brian J. Beesley" <[EMAIL PROTECTED]>
Subject: Re: Mersenne: v19 and priorities
On 17 Dec 99, at 16:35, Gordon Bower wrote:
> Something strange happened, though. Version 19 slows down considerably
> more in response to my doing other low-demand things on my machine,
> reading email/web browsing/etc. Is this just in the nature of v19,
> something to do with the optimizations that were added to speed it up? (It
> does still average a faster rate in the long run).
Very likely this is the case. The new code is better tuned to the
hardware - making more efficient use of the cache - if something else
makes demands on the same cache, there's bound to be a hit of some
sort. I would guess that with a moderate load of active "normal"
applications on the system, v18 & v19 would run at about the same
speed. Of course, v19 would slow down more since it's starting at a
faster speed.
>
> As long as I am writing to the list -- perhaps someone could explain in a
> little more detail than readme.txt does as to what the valid range of
> values for the Priority variable are and what the effect of each is on NT
> and 95? I experimented a little by trial and error last summer when a
> friend running a 3-D screen saver offered to let me run the program on his
> machine, but we never had much success fine-tuning it so as to not
> interfere with his work.
The valid range is 0-15.
If you specify 0, you will lose half your CPU to the OS's native
cycle sink. This is probably not what you want.
Screen savers normally run at priority 4, normal applications at 8.
If you set a CPU-intensive program to run above priority 8, your
"normal" activities will be badly impacted. If you go above 10 or 11,
you can expect to start to get problems with device drivers for
modems etc. If you try 14 or 15, you will very likely lose control of
your system altogether.
If you really need to run a screensaver as well as Prime95, I'd
reccomend setting Prime95 at priority 4 so that it shares cycles
about equally with the screensaver.
Regards
Brian Beesley
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------------------------------
Date: Sat, 18 Dec 1999 16:50:52 +0100
From: "Fran�ois Perruchaud" <[EMAIL PROTECTED]>
Subject: Mersenne: Fibonacci Series
An old book of mine gives without proof an example of Fibonacci Sequence
that countains no primes, but where U(1) and U(2) are co-prime.
The sequence was found by R. L. Graham.
Reference :
"A Fibonacci-like sequence of composite numbers",
R.L. Graham, Math. Mag. 37, 1964.
U(1) = 1786772701928802632268715130455793
U(2) = 1059683225053915111058165141686995
U(N+2) = U(N+1) + U(N)
I only verified with Mapple that U(1) and U(2) are co-prime
and that U(N) is composite for N<10.
>On Fri, 17 Dec 1999, Griffith, Shaun wrote:
>> Ian McLoughlin wrote:
>> > Since the list is quiet...
>> > Does a Fibonnacci series contain a finite or an infinite number of
primes?
>> > From what I understand..
>> > In a gen.F sequence if the first two numbers are divisible by a prime
all
>> > its numbers are divisible by the same prime, if the first two numbers
are
>> > co-prime is there a generalised sequence that contains NO PRIMES....
>>
>> The generalized Fibonacci sequence seems to generate at least one prime
>> regardless of the values assigned to Fib(1), Fib(2), *unless* Fib(1) and
>> Fib(2) are even. Then there is never an odd number, and never a chance
for a
>If they are both even they aren't coprime. :)
>
>> prime after Fib(2) (though Fib(1) or Fib(2) may be =2, but that seems
>> trivial).
>>
>> I tried it with composite odd numbers, such as 15,77, which happen to be
>> coprime. The first 3 primes generated are Fib(7)=691, Fib(14)=20101, and
>> Fib(28)=16945081.
>>
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------------------------------
Date: Sat, 18 Dec 1999 11:35:19 -0500
From: "Frank_A_L_I_N_Y" <[EMAIL PROTECTED]>
Subject: Mersenne: my disk needed a reload
I had to reload my hard drive.
Lost my exponent, exe, worktodo file
I was 2 weeks in
Would like to "give back" the number so we don't waste 6 weeks of the 2
month time limit.
How do I do this.
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Date: Sat, 18 Dec 1999 15:09:17 -0500
From: Jud McCranie <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Fibonacci Series
- --=====================_194721962==_.ALT
Content-Type: text/plain; charset="iso-8859-1"; format=flowed
Content-Transfer-Encoding: quoted-printable
At 04:50 PM 12/18/99 +0100, Fran=E7ois Perruchaud wrote:
>An old book of mine gives without proof an example of Fibonacci Sequence
>that countains no primes, but where U(1) and U(2) are co-prime.
>The sequence was found by R. L. Graham.
>Reference :
>"A Fibonacci-like sequence of composite numbers",
>R.L. Graham, Math. Mag. 37, 1964.
>
>U(1) =3D 1786772701928802632268715130455793
>U(2) =3D 1059683225053915111058165141686995
>U(N+2) =3D U(N+1) + U(N)
>
>I only verified with Mapple that U(1) and U(2) are co-prime
>and that U(N) is composite for N<10.
I checked a few thousand terms, and they were all composite.
+--------------------------------------------------------+
| Jud McCranie |
| |
| 137*2^197783+1 is prime! (59,541 digits, 11/11/99) |
+--------------------------------------------------------+
- --=====================_194721962==_.ALT
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<html>
At 04:50 PM 12/18/99 +0100, Fran=E7ois Perruchaud wrote:<br>
<blockquote type=3Dcite cite>An old book of mine gives without proof an
example of Fibonacci Sequence<br>
that countains no primes, but where U(1) and U(2) are co-prime.<br>
The sequence was found by R. L. Graham.<br>
Reference :<br>
"A Fibonacci-like sequence of composite numbers",<br>
R.L. Graham, Math. Mag. 37, 1964.<br>
<br>
U(1) =3D 1786772701928802632268715130455793<br>
U(2) =3D 1059683225053915111058165141686995<br>
U(N+2) =3D U(N+1) + U(N)<br>
<br>
I only verified with Mapple that U(1) and U(2) are co-prime<br>
and that U(N) is composite for N<10.</blockquote><br>
I checked a few thousand terms, and they were all composite.<br>
<br>
<div>+--------------------------------------------------------+</div>
<div>| &nbs=
p;
Jud
McCranie &n=
bsp; =
|</div>
<div>| &nbs=
p; &n=
bsp; =
&nbs=
p;
|</div>
<div>| 137*2^197783+1 is prime! (59,541 digits,
11/11/99) |</div>
<div>+--------------------------------------------------------+</div>
</html>
- --=====================_194721962==_.ALT--
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Date: Sat, 18 Dec 1999 22:34:10 -0500
From: "Chris Nash" <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Fibonacci Series
Hi folks
>U(1) = 1786772701928802632268715130455793
>U(2) = 1059683225053915111058165141686995
>U(N+2) = U(N+1) + U(N)
>I checked a few thousand terms, and they were all composite.
There is almost certainly a 'covering set' of divisors. In essence you need
to find a set of primes P and a modulus M, then prove that U(N) has a factor
in P specified by the value of N mod M.
Chris Nash
Lexington KY
UNITED STATES
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Date: Mon, 20 Dec 1999 03:26:27 +0100 (MET)
From: [EMAIL PROTECTED]
Subject: Re: Mersenne: Fibonacci series..
"Ian L McLoughlin" <[EMAIL PROTECTED]> asks
> Since the list is quiet...
> Does a Fibonnacci series contain a finite or an infinite number of primes?
> From what I understand..
> In a gen.F sequence if the first two numbers are divisible by a prime all
> its numbers are divisible by the same prime, if the first two numbers are
> co-prime is there a generalised sequence that contains NO PRIMES....
This is part of problem A3 in Richard K. Guy's
`Unsolved Problems in Number Theory', Second Edition,
Springer-Verlag, 1994. This book could make a good
Christmas gift to your number theory friends.
Richard Guy gives solutions starting with
1786 772701 928802 632268 715130 455793
1059 683225 053915 111058 165141 686995 (Graham)
and
49463 435743 205665
62638 280004 239857 (Knuth)
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------------------------------
End of Mersenne Digest V1 #672
******************************
