To be removed soon:   language help

Yves Gallot's GFN Search Project


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): p163, g289, g297, g303, g308 ... ... g363, g379, g390, g410, g419
Active wild codes: GF\d+,GC\d+
E-mail address: (e-mail address unpublished)
Web page:
Username: GFNSearch (entry created on 04/14/2005)
Database id:753 (entry last modified on 06/02/2020)
Active primes:on current list: 4, rank by number 17
Total primes: number ever on any list: 381.5
Production score: for current list 46 (normalized: 13), total 47.3054, rank by score 17
Largest prime: 1372930131072 + 1 ‏(‎804474 digits) via code g236 on 09/22/2003
Most recent: 9850333616384 + 1 ‏(‎130965 digits) via code g419 on 05/13/2009
Entrance Rank: mean 26.12 (minimum 5, maximum 60)

Descriptive Data: (report abuse)

Yves Gallot's home page for this project states in part

During the 17th century, Pierre de Fermat and Marin Mersenne studied two particular forms of numbers, thinking that they could produce a large amount of prime numbers or even to be ever prime. Mersenne communicated a list of the primes of the form 2n-1, for all n < 257. It required many years of labour to produce a correct version of the list, which is close to Mersenne's list. In his correspondence with Frénicle, Fermat expressed his conviction that if n is a power of 2, then 2n+1 is a prime. Fermat knew that 3, 5, 17, 257 and 65537 are primes but later Euler showed that Fermat's conjecture is false by discovering a factor to the next number.

In honour of the inspired pioneers, the numbers of the form 2n-1 are now called the Mersenne numbers and the numbers of the form 2n+1 the Fermat numbers. The search for Mersenne and Fermat primes has been greatly extended since the 17th century. Today, all the Mersenne primes having less than 2,000,000 digits are known and all the Fermat primes up to 2,000,000,000 digits! It was possible because during the 19th century some efficient tests were discovered to check the primality of these numbers. But at the same time, some tests as fast were also found to test check the primality of all the numbers N where the factorization of N-1 or N+1 is known. Then many forms could be used to find the largest known prime but surprisingly the search was almost restricted to the Mersenne numbers. The famous exceptions were (2148+1)/17 (identified in 1951 by A. Ferrier by using hand computing method), 180.(2127-1)2+1 (discovered in 1951 by Miller and Wheeler) and 391581.2216193-1 (found by the "Amdahl 6" in 1989).

In 1998, Y. Gallot remarked that the Discrete Weighted Transform is a polynomial operation and that if the representation of the numbers is not limited to the base 2, then many numbers can be tested at the same speed as a Mersenne number: the Generalized Fermat Numbers which are the numbers of the form bn+1, where n is a power of 2. He implemented the algorithm in 1999 in Proth.exe and since, he has been optimizing. The theoretical hypothesis is now a reality: the search for Generalized Fermat primes is as fast as the search for a Mersenne primes of the same size. With few tens of computers, many primes having more than 100,000 digits were quickly found, the largest of them has more than 800,000 digits. In 2002, P. Carmody together with B. Frey made great strides in a Generalized Fermat Number sieving algorithm. P. Carmody  is organizing a massive sieving effort, with a powerful program written by D. Underbakke, that even speeds up the Generalized Fermat Numbers Search.

Generalized Fermat Numbers are more numerous than Mersenne numbers at equal size and many of them are waiting to be discovered to fill the gaps between the Mersenne primes already found or not yet found. If you are interested in the search for the primes of the 21st century, you are welcome to the Generalized Fermat Prime Search!

Error in data above: HTML_Tidy reports: line 33 column 14 - Warning: inserting implicit <p> line 33 column 14 - Warning: trimming empty <p>

I found a prime as a member of this group and I would like to

Surname: GFNSearch (used for alphabetizing and in codes)
Unverified primes are omitted from counts and lists until verification completed.
I administer Yves Gallot's GFN Search Project and I would like to
Edit this page
Printed from the PrimePages <> © Chris Caldwell.