- Hi Jarek,
congrats, very nice finds again!
BTW, did you use any additional (public) programs for sieving/prp-
/primetest beside your own programs?
I need to know this for the update of the CC record list where I
normally list all used programs.
--- In email@example.com, Jaroslaw.Wroblewski@... wrote:
> Yestyerday I have found 2 new CC17:
> CC17 2nd kind: 40244844789379926979141
> CC17 2nd kind: 127806074555607670094731
> Both were verified by Jens yesterday (I am on a short vacation with
> mobile phone internet access only).
> Today I worked out a way to verify them myself and (I hope) to post
> I have also found the largest known CC15:
> CC15 2nd kind: 2817673877915370357723841
- Today I have discovered new largest CC16 (also new 16 Simultaneous
CC16, 2nd kind: 258296136493222766530021 (24 digits)
It is a tiny improvement of the previous best 255... (also 24 digits)
being a part of a CC17.
All my Cunningham Chains search, which has already been going for
about two weeks, is conducted by my own program written in C and run
on 28 64-bit computers at Mathematical Institute of Wroclaw University.
Primality check inside the program is performed by calling GMP function
The sieving algorithm is of my own design and implemented by
using basic C operations only, with very little memory (probably
processor's cache is enough on most computers).
- I have just discovered:
CC17, 2nd kind: 1302312696655394336638441 (25 digits)
CC15, 2nd kind: 5830768257311375388822241 (25 digits)
I have given up searching for CC17 and wanted to improve the largest
known CC16, so I have shifted my search to larger numbers this
morning, which wouldn't be a smart thing to do if I intended to hunt
for another CC17. After 9.5 hours of 28 computers work, the above were
the only 2 CC's longer than 14. Given the data collected during this
9.5 hour search I think I deserved to find 3 CC15's and a half of
CC16. I was counting on a CC16 by tomorrow morning, but a CC17 today
is a very nice surprise :-)
- I have discovered:
CC16, 2nd kind: 20193491108493165642344881 (26 digits)
CC15, 2nd kind: 71838292723844326926417601 (26 digits)
- --- In firstname.lastname@example.org, "jarek372000"
>Congratulations for improving the CC15 and CC16 records by another
> I have discovered:
> CC16, 2nd kind: 20193491108493165642344881 (26 digits)
> CC15, 2nd kind: 71838292723844326926417601 (26 digits)
Finally I managed to update the record list in the Files section. Jens
Kruse Andersen will update the corresponding web page.
Currently I am hunting for a 31 digit CC15 (2nd kind). After 40 hours
of 29 computers work I have 2 CC14:
CC14, 2nd kind: 2354904873485081880414653783011 (31 digits)
CC14, 2nd kind: 756623498046318886601149174501 (30 digits)
and 21 CC13 in 30-32 digits, with the top 3 being:
CC13, 2nd kind: 71893041796676884721115682595521 (32 digits)
CC13, 2nd kind: 71183625845277875816974563041281 (32 digits)
CC13, 2nd kind: 61769341861507223234745310908481 (32 digits)
2008/6/14, Dirk Augustin <Dirk_Augustin@...>:
> --- In email@example.com, "jarek372000"
> <Jaroslaw.Wroblewski@...> wrote:
>> I have discovered:
>> CC16, 2nd kind: 20193491108493165642344881 (26 digits)
>> CC15, 2nd kind: 71838292723844326926417601 (26 digits)
> Congratulations for improving the CC15 and CC16 records by another
> Finally I managed to update the record list in the Files section. Jens
> Kruse Andersen will update the corresponding web page.
> Unsubscribe by an email to: firstname.lastname@example.org
> The Prime Pages : http://www.primepages.org/
> Yahoo! Groups Links
- After over 9 days of 30 computers work I have discovered:
CC16, 2nd kind: 2368823992523350998418445521 (28 digits)
It has 30 digit 8th term:
which is responsible for 16 Simultaneous Primes score.
I am resending this message as the previous one seems to have been
corrupted. My apologies if you get it twice.
- Jarek wrote:
> CC16, 2nd kind: 2368823992523350998418445521 (28 digits)Congratulations on your sixth improvement of this record in a month:
> It has 30 digit 8th term:
> which is responsible for 16 Simultaneous Primes score.
Jens Kruse Andersen
- I have found a new record for 15 Largest Known Simultaneous Primes:
CC15 (1st kind, 41 digit first term):
(Apr 25, 2014, Jaroslaw Wroblewski)
43 digit 8-th term 3501285206294480290959130236854866515421439
I applied a litlle trick, namely created and used polynomial
P(x) = 86730930*x^2,
which has nice property of having over-average density of Cunningham Chains
The above Cunningham Chain is obtained for
x=17759132926784169, so it can also be written as
86730930*17759132926784169^2 * 2^n - 1, n=0..14
The search was very lucky (only one CC13 and the above CC15 was found)
and short (2 hours of 60 threads).