M48 normally refers to the 48th Mersenne prime, in order of size from the smallest to greatest. This is the primary usage and what is referred to in the rest of this article. For clarification about other possible usages refer to the Nomenclature and notation article.
The official discovery date for 257,885,161-1 was 2013-01-25. See the press release for the full description of this discovery.
The volunteers that ran these tests were:
- Serge Batalov, who ran Ernst Mayer's Mlucas software on a 32 core server for 6 days (resource donated by Novartis IT group)
- Jerry Hallett, who ran CUDALucas on an NVIDIA GPU for 3.6 days
- Dr. Jeff Gilchrist, who ran two separate tests:
- New Largest Known Prime Number 257,885,161-1 at YouTube channel Numberphile