On 23 May 2015, 17:47:52 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=144052 by finding the mega prime:
The prime is 1,410,730 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 36 k's now remain in the Sierpinski Base 5 Problem.
The discovery was made by Wolfgang Schmidt (Artist) of Germany using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 16GB RAM running Linux. This computer took about 6 hours and 17 minutes to complete the primality test using LLR. Wolfgang is a member of the Special: Off-Topic team.
The prime was verified on 26 May 2015, 17:48:33 UTC, by user RoBorg of the United Kingdom using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 8GB RAM running Microsoft Windows 7 Professional. This computer took about 15 hours and 24 minutes to complete the primality test using LLR. RoBorg is a member of the Brony@Home team.
For more details, please see the official announcement.