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Dutch IMO TST
2021 Dutch IMO TST
4
p is a divisor of 5^m7^n-1
p is a divisor of 5^m7^n-1
Source: 2021 Dutch IMO TST 3.4
December 28, 2021
number theory
divisor
Problem Statement
Let
p
>
10
p > 10
p
>
10
be prime. Prove that there are positive integers
m
m
m
and
n
n
n
with
m
+
n
<
p
m + n < p
m
+
n
<
p
exist for which
p
p
p
is a divisor of
5
m
7
n
ā
1
5^m7^n-1
5
m
7
n
ā
1
.
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