Mastodawn

Breaking news from #PrimeGrid: the first GFN-21, a Generalised Fermat Prime (of the form b^2^n+1) with n=21, has been found, and it's over 13 million digits long!!

More details, including the exact number, will be confirmed soon (EDIT: 2524190^2^21+1), but it'll be the 6th largest known prime, the largest prime found by PrimeGrid, and the new largest known non-Mersenne prime!