Proof-code: x25
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  Samuel Yates began, and this site continues, a database of the largest known primes. Primes in that database are assigned a proof-code to show who should be credited with the discovery as well as what programs and projects they used. (Discoverers have one prover-entry, but may have many proof-codes because they use a variety of programs...) This page provides data on x25, one of those codes.

Code name (*):x25   (See the descriptive data below.)
Persons (*):2 (counting humans only)
Projects (*):0 (counting projects only)
Display (HTML):Water, Broadhurst, Primo, OpenPFGW
Number of primes:total 251
Unverified Primes:0 (prime table entries marked 'Composite','Untested', or 'InProcess')
Score for Primes (*):total 39.1467, on current list 37.8264
Entrance Rank (*):mean 23049.77 (minimum 10116, maximum 32058)

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This code is used for proofs of generalized Lucas and Lehmer numbers and their primitive parts.

The following software was used:

(1) Pari-GP for cyclotomic (and, where appropriate, Aurifeuillian) factorizations of N^2-1.

(2) GMP-ECM, Msieve and ggnfs for extracting PrP factors of such cyclotomic cofactors.

(3) Primo and VFYPR for proving these helpers prime.

(4) OpenPFGW for BLS tests with these prime helpers.

(5) Pari-GP for Williams-Lenstra or Konyagin-Pomerance proofs, where BLS was insufficient.

By far the largest effort was expended on GMP-ECM. Factorization percentages for current top-20s are listed at this yahoo page, in the cases primV and lucasU, and here, in the case of Lehmer numbers.

PS: We also included:

6738*(2^148227+60443)*(205*2^65523-1639)-1, with a Konyagin-Pomerance proof that depends on the cyclotomy of 2^65520-1.

Two gigantic generalized repunits, with BLS proofs involving ECPP helpers at 3832 and 4354 digits.

Below is additional information about this entry.
Display (text):Water, Broadhurst, Primo, OpenPFGW
Display (short):Water & Broadhurst
Database id:113 (do not use this database id, it is subject to change)
Proof program:(see the descriptive data above)
Entry last modified:2009-11-21 21:20:36