Riesel Prime Search

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 reflects on the primes currently on the list. (Many of the terms that are used here are explained on another page.)

Proof-code(s):

E-mail address:

kosmaj

(at)

yahoo

(dot)

com

Web page:

http://www.mersenneforum.org/forumdisplay.php?f=59

Username

RPS

(entry created on 10/31/2005 04:23:42 UTC)

Database id:

819

(entry last modified on 9/2/2026 21:28:36 UTC)

Active primes:

on current list: 93.5, rank by number 3

Total primes:

number ever on any list: 4481

Production score:

for current list 52 (normalized: 361), total 52.7272, rank by score 6

Largest prime:

71 · 2^9161150 - 1 ‏(‎2757783 digits) via code A100 on 8/30/2026 20:04:57 UTC

Most recent:

463 · 2^3108775 - 1 ‏(‎935838 digits) via code A100 on 9/2/2026 22:12:27 UTC

Entrance Rank:

mean 463.93 (minimum 25, maximum 4917)

Descriptive Data: (report abuse)

The "Riesel Prime Search" project is searching for Riesel primes k*2^n-1, k>1. We have three subprojects as follows.
(1) k's that can produce many primes in the given range of exponent n,
(2) low-weight k's that produce a very small number of primes [opposite to (1) above],
(3) small k < 300 (with exception of those k's already reserved by other projects).

How To Join
Everybody is welcome to join the project. Just visit the forum link given above, have a look what's going on, and reserve your first file to test!

Software Used
Primality Testing: LLR. pfgw and Proth.exe used for small exponents (less than 10k or 20k) and for double-checking.
Sieving: srsieve and NewPGen.

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

I administer Riesel Prime Search and I would like to