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Baltic Way
2000 Baltic Way
13
13
Part of
2000 Baltic Way
Problems
(1)
n must be a prime power
Source: Baltic Way 2000
12/17/2010
Let
a
1
,
a
2
,
…
,
a
n
a_1,a_2 ,\ldots, a_n
a
1
,
a
2
,
…
,
a
n
be an arithmetic progression of integers such that
i
∣
a
i
i|a_i
i
∣
a
i
for
i
=
1
,
2
,
…
,
n
−
1
i=1, 2,\ldots ,n-1
i
=
1
,
2
,
…
,
n
−
1
and
n
∤
a
n
n\nmid a_n
n
∤
a
n
. Prove that
n
n
n
is a prime power.
arithmetic sequence
number theory proposed
number theory