math
posted by jack on .
Find the sum of all primes p, such that p divides up, where up is the p th Fibonacci number.
please tell me the answer it's urgent about this..///

If we use binets formula for the fibonacci numbers we can trivially see that Fp=5^(p1)/2 mod p implying that the only prime p such that p divides Fp is 5 divides F5=5.