David Underbakke's GenefX64
(Another of the Prime Pages' resources)
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program A titan, as defined by Samuel Yates, is anyone who has found a titanic prime. This page provides data on those that have found these primes. The data below only reflect on the primes currently on the list. (Many of the terms that are used here are explained on another page.)

Proof-code(s): p259, p314, p320, p309, L3209, g429
E-mail address:
Web page:http://www.underbakke.com/genefer
Username: GenefX64 (entry created on 10/14/2009)
Database id:2015 (entry last modified on 02/05/2013)
Program Does *: special
Active primes:on current list: 6, rank by number 27
Total primes: number ever on any list: 6
Production score: for current list 50 (normalized: 571), rank by score 21
Largest prime: 356926524288 + 1 ‏(‎2911151 digits) via code L3209 on 07/25/2012
Most recent: 689186131072 + 1 ‏(‎765243 digits) via code g429 on 02/05/2013
Entrance Rank: mean 73.00 (minimum 11, maximum 226)

Descriptive Data: (report abuse)

GenefX64 is a derived work based upon algorithms by Yves Gallot. It is a 64-bit windows command line program for testing Generalized Fermat primes (b^2^n+1). It is designed to utilize SSE2/SSE3, optimized for x86-64, and fastest on Intel Core 2 (or above) processors and AMD Family 10h processors (Phemon and newest Athlon X2). SSE3 support is required. See the web page for additional details.

For details on the original algorithm, see Yves Gallot's genefer.c program which can be found at http://pagesperso-orange.fr/yves.gallot/primes/download.html.

Mark Rodenkirch assisted with many of the new features such as the checkpoint file, quick calculate mode, progress reporting, and residual values. Look for Mac Intel and PPC versions from him in the near future.

Note: This program identifies probable primes. The probable prime must be proven with another program before being submitted.

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Surname: GenefX64 (used for alphabetizing and in codes)
Unverified primes are omitted from counts and lists until verification completed.