On 4 December 2013, 20:53:51 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=173198 by finding the mega prime:
The prime is 1,018,959 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 67th overall. This is the first known base 5 mega prime. 88 k's now remain in the Riesel Base 5 Problem.
The discovery was made by Motohiro Ohno (syusui) of Japan using an Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz with 4GB RAM running Microsoft Windows 7 Home Premium. This computer took about 22 hours and 29 minutes to complete the primality test using LLR. Motohiro is a member of the Team 2ch team.
The prime was verified on 6 December 2013 5:27:38 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 8 GB RAM running Microsoft Windows 7 Home Premium. This computer took about 33 hours and 22 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.
For more details, please see the official announcement.
My lucky number is 75898524288+1