March was a special month for the Extended Sierpinski Problem (ESP) on PrimeGrid's PRPnet. After two years of crunching with no prime finds, two more k's were eliminated:
The first discovery was made by Timothy D. Winslow (Pooh Bear 27) of the United States on Wednesday 14th of March 2012. 123287*2^2538167+1 is prime and at 764070 digits entered Chris Caldwell's Top 5000 list as the 78th largest prime.
The second discovery was made by Rodger Ewing (Pilgrim) of the United States on Tuesday 27th of March 2012. 147559*2^2562218+1 is prime and at 771310 digits entered Chris Caldwell's Top 5000 list as the 77th largest prime.
15 k's now remain.
Congratulations to both Rodger and Tim! The next ESP find will very likely also be a Mega Prime!
For more information about the Extended Sierpinski Problem, see this forum post.
141941*2^4299438-1 is prime!