Thanks everyone, it's a big find, and everyone who contributed -- with math theory, programming, sieving, and PRP tests -- had a part in finding that number. My only skill was being lucky.
Now for the fun part -- with such short run-times on the two GFNs that were found with GeneferCUDA, lots of people had the same thought: Can we up the ante a bit and try to get not just a new world record GFN prime, but a world record prime? For many years, the largest prime has been a Mersenne prime, and for good reason: those are the easiest to search for. In fact, right now, not only is the largest known prime a Mersenne prime, but the largest 9 primes are all Mersenne primes.
There may be an opportunity here to find a GFN that's an even larger prime. If anyone is interested, hop on over to
this thread.