Thread: Generalized Mersenne Primes View Single Post
 2012-10-27, 19:14 #4 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 22·3·7·109 Posts For even values of n (and not coprime a,b), indeed, you can arrive to some convenient cancellations (a+b will have to be 2*gcd(a,b)n, where n will be a power of two) and get an extended Generalized Fermat in disguise. E.g. (6^4+26^4)/(6+26) is xGF'(3,13,4).