Preprint: dvi (6K), pdf (82K), ps (40K).
Extended version: dvi (10K), pdf (149K), ps (51K).
and its reciprocal. This completes the search for primitive trinomials whose degree is a Mersenne exponent less than ten million.
The search for degree 6972593 was performed on an average of about 300 processors and took approximately 230,000 Mips-years. The computation was started on 6 February 2001 and completed on 25 July 2003.
The primitive trinomial of degree 6972593 was found on 31 August 2002. The announcement is here, or see the September 2002 archives of the Number Theory List (NBMBTHRY) for a version with links.