Problems & Puzzles: Problems Problem 10. Find a 500digit prime p and positive integers x, y Find a 500digit prime p and positive integers x, y such that (p1)/2 is prime, p divides 4^x  9, and p divides 4^y  25". Bernstein says "I'll pay $100 for the first published example of p, x, y". Problem posed by D. J. Bernstein (30/06/98), pointed out to me by mail by Samuli Larvala at 18/08/98.





