U(21412, 1, 4620) - U(21412, 1, 4619)
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At this site we maintain a list of the 5000 Largest Known Primes which is updated hourly. This list is the most important databases at The Prime Pages: a collection of research, records and results all about prime numbers. This page summarizes our information about one of these primes.

This prime's information:

field (help)value
Description:U(21412, 1, 4620) - U(21412, 1, 4619)
Verification status (*):PRP
Official Comment:Lehmer number
Unofficial Comments:This prime has 1 user comment below.
Proof-code(s): (*):x25 : Water, Broadhurst, Primo, OpenPFGW
Decimal Digits:20004   (log10 is 20003.305742473)
Rank (*):63609 (digit rank is 2)
Entrance Rank (*):61578
Currently on list? (*):short
Submitted:6/8/2016 19:49:28 CDT
Last modified:6/8/2016 20:20:37 CDT
Database id:121751
Status Flags:Verify, TrialDiv
Score (*):34.5868 (normalized score 0.0001)

Archival tags:

There are certain forms classed as archivable: these prime may (at times) remain on this list even if they do not make the Top 5000 proper.  Such primes are tracked with archival tags.
Lehmer number (archivable *)
Prime on list: yes, rank 12
Subcategory: "Lehmer number"
(archival tag id 218346, tag last modified 2017-06-28 15:50:31)

User comments about this prime (disclaimer):

User comments are allowed to convey mathematical information about this number, how it was proven prime.... See our guidelines and restrictions.

David Broadhurst writes (8 Jun 2016): 
CHG proof at 20004 digits and 28.05% factorization

Verification data:

The Top 5000 Primes is a list for proven primes only. In order to maintain the integrity of this list, we seek to verify the primality of all submissions.  We are currently unable to check all proofs (ECPP, KP, ...), but we will at least trial divide and PRP check every entry before it is included in the list.
fieldvalue
prime_id121751
person_id9
machineUsing: Xeon 4c+4c 3.5GHz
whatprp
notesCommand: /home/caldwell/client/pfgw/pfgw64 -tc -q"lucasU(21412,1,4620)-lucasU(21412,1,4619)" 2>&1
PFGW Version 3.7.7.64BIT.20130722.x86_Dev [GWNUM 27.11]
Primality testing lucasU(21412,1,4620)-lucasU(21412,1,4619) [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 37
Running N-1 test using base 59
Running N+1 test using discriminant 67, base 15+sqrt(67)
Calling N-1 BLS with factored part 1.16% and helper 0.53% (4.00% proof)


lucasU(21412,1,4620)-lucasU(21412,1,4619) is Fermat and Lucas PRP! (42.7255s+0.0028s)
[Elapsed time: 43.00 seconds]
modified2017-01-27 05:57:11
created2016-06-08 19:51:01
id167389

Query times: 0.0004 seconds to select prime, 0.0003 seconds to seek comments.