I am glad to announce that the number 6753^5122+5122^6753 is prime
(a number taken from Paul Leyland's tables, see
http://www.leyland.vispa.com/numth/primes/xyyx.htm).
It has 25050 decimal digits and was proven prime using fastECPP.
Calendar time was 2010/09/01 -- 2010/10/15. Computations were done on a
network of bi-core i7 quad-core using GMP-5.0.2, mpfr, mpc, mpfrcx, open MPI.
Computing the DOWNRUN sequence took 1696 days, and the proving part 282 days
(among which only 5 days for computing the class polynomials).
The gzipped certificate of the 2024 steps needs 55 Mb. Checking this
certificate on a single machine takes 8 days. The certificate is available
at:
http://www.lix.polytechnique.fr/Labo/Francois.Morain/Primes/Certif/x6753y5122.certif.gz
F. Morain