Top project sorted by score

At this site we keep several lists of primes, most notably the list of the 5,000 largest known primes. Who found the most of these record primes? We keep separate counts for persons, projects and programs. To see these lists click on 'number' to the right.

Clearly one 100,000,000 digit prime is much harder to discover than quite a few 100,000 digit primes. Based on the usual estimates we score the top persons, provers and projects by adding ‎(log n)³ log log n‎ for each of their primes n. Click on 'score' to see these lists.

Finally, to make sense of the score values, we normalize them by dividing by the current score of the 5000th prime. See these by clicking on 'normalized score' in the table on the right.

rank project primes score 1 Great Internet Mersenne Prime Search by Woltman & Kurowski 18 58.5540 2 PrimeGrid 4092.5 56.5007 3 Prime Internet Eisenstein Search 30 55.0414 4 Conjectures 'R Us 223.5 53.1886 5 Seventeen or Bust 6.5 53.0183 6 Riesel Prime Search 92.5 52.1927 7 The Prime Sierpinski Problem 2 51.4713 8 No Prime Left Behind (formerly: PrimeSearch) 47 50.9599 9 Twin Prime Search 60 50.3947 10 Science United 2.5 50.2219 11 primecrunch.com 10 49.3991 12 12121 Search 1.5 49.3399 13 Private GFN server 16.5 49.3091 14 Sierpinski/Riesel Base 5 5 49.1267 15 Riesel Sieve Project 2.5 47.6367 16 Rechenkraft.net e.V. 1.5 47.5265 17 The Other Prime Search 14 47.5237 18 321search 1.5 47.2705 19 SRBase 1 46.9962 20 Primeform e-group 65 31.2950

Notes:

Score for Primes

To find the score for a person, program or project's primes, we give each prime n the score (log n)³ log log n; and then find the sum of the scores of their primes. For persons (and for projects), if three go together to find the prime, each gets one-third of the score. Finally we take the log of the resulting sum to narrow the range of the resulting scores. (Throughout this page log is the natural logarithm.)

How did we settle on (log n)³ log log n? For most of the primes on the list the primality testing algorithms take roughly O(log(n)) steps where the steps each take a set number of multiplications. FFT multiplications take about

O( log n ^. log log n ^. log log log n )

operations. However, for practical purposes the O(log log log n) is a constant for this range number (it is the precision of numbers used during the FFT, 64 bits suffices for numbers under about 2,000,000 digits).

Next, by the prime number theorem, the number of integers we must test before finding a prime the size of n is O(log n) (only the constant is effected by prescreening using trial division).  So to get a rough estimate of the amount of time to find a prime the size of n, we just multiply these together and we get

O( (log n)³ log log n ).

Finally, for convenience when we add these scores, we take the log of the result.  This is because log n is roughly 2.3 times the number of digits in the prime n, so (log n)³ is quite large for many of the primes on the list. (The number of decimal digits in n is floor((log n)/(log 10)+1)).