20150703, 08:26  #1 
Nov 2008
503 Posts 
Since when was 4096 prime?
In the recently cleared exponents list is this little entry
Jacques MOLNE mon_4 4096 FECM 20150703 00:08 5.5 1.0369 45477879701734570611058964078361695337745924097 Thought all exponents had to be prime which clearly an even number isn't (apart from 2 to head off RDS) 
20150703, 08:33  #2 
Jun 2003
2×2,683 Posts 
FECM stands for FermatECM. This is a result of ECM run on 2^4096+1. Incidentally, the factor found is a composite one consisting of some of the previouslyknown factors for that number. As for "should it be there in the cleared exponents list", I'll let the project admins make that decision.

20150703, 15:37  #3  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
3·11·157 Posts 
Quote:
I suspect NONE of these 113 are NEW. Code:
Top ECM on Fermat numbers producers for the last year. Total  Rank Change  Overtake date based on Rank Member Name GHzDays Attempts Successes 90day 30day 7 day 1 day  90 days 30 days 7 days              1 David Bessell 43850.855 6261 0   >999dy 2 Jacques MOLNE 33930.562 2831 113   Code:
PrimeNet Most Recent Cleared NotPrime This report updates every hour on the hour. This report produced 20150703 15:00 UTC Member Name Computer Name Exponent Type UTC Time Received Days GHzdays Result Jacques MOLNE mon_4 4096 FECM 20150703 10:05 5.9 1.0369 45477879701734570611058964078361695337745924097 Jacques MOLNE mon_4 4096 FECM 20150703 00:08 5.5 1.0369 45477879701734570611058964078361695337745924097 Jacques MOLNE mon_4 4096 FECM 20150702 17:33 5.2 1.0369 45477879701734570611058964078361695337745924097 Jacques MOLNE mon_4 4096 FECM 20150702 06:30 4.7 1.0369 45477879701734570611058964078361695337745924097 ECM2=k,b,n,c,B1,B2,curves_to_run[,"commaseparatedlistofknownfactors"] Last fiddled with by petrw1 on 20150703 at 15:40 Reason: ECM2=... 

20150704, 03:19  #4  
∂^{2}ω=0
Sep 2002
República de California
2DD0_{16} Posts 
Quote:


20150704, 08:26  #5  
Einyen
Dec 2003
Denmark
6361_{8} Posts 
Quote:
Edit: Except 0 and 1 I guess. Last fiddled with by ATH on 20150704 at 08:43 

20150704, 09:25  #6  
Jun 2003
1010011110110_{2} Posts 
Quote:
Consider the polynomial b^4 + 8*b^2 + 15 = (b^2+3)*(b^2+5) represented by the digits 1080F. This can never yield a prime (not even in negative bases). 

20150704, 17:30  #7 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
3×29×113 Posts 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
(M48) NEW MERSENNE PRIME! LARGEST PRIME NUMBER DISCOVERED!  dabaichi  News  571  20201026 11:02 
Twin Prime Days, Prime Day Clusters  cuBerBruce  Puzzles  3  20141201 18:15 
disk died, prime work lost forever? where to put prime? on SSD or HDD?  emily  PrimeNet  3  20130301 05:49 
The 40th known Mersenne prime, 2209960111 is not PRIME!  illmanq  Miscellaneous Math  33  20040919 05:02 
4096 P4 help wanted  Tasuke  Hardware  17  20020823 22:06 