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Iran MO (3rd Round)
2004 Iran MO (3rd Round)
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21
Part of
2004 Iran MO (3rd Round)
Problems
(1)
p|a_1^k + ... + a_n^k for infinitely many p
Source: Iranian National Olympiad (3rd Round) 2004
1/9/2009
a
1
,
a
2
,
…
,
a
n
a_1, a_2, \ldots, a_n
a
1
,
a
2
,
…
,
a
n
are integers, not all equal. Prove that there exist infinitely many prime numbers
p
p
p
such that for some
k
k
k
p\mid a_1^k \plus{} \dots \plus{} a_n^k.
number theory
greatest common divisor
modular arithmetic
prime numbers
number theory proposed