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Putnam
2023 Putnam
B5
2023 Putnam B5
2023 Putnam B5
Source:
December 3, 2023
Putnam
Putnam 2023
Problem Statement
Determine which positive integers
n
n
n
have the following property: For all integers
m
m
m
that are relatively prime to
n
n
n
, there exists a permutation
π
:
{
1
,
2
,
…
,
n
}
→
{
1
,
2
,
…
,
n
}
\pi:\{1,2, \ldots, n\} \rightarrow\{1,2, \ldots, n\}
π
:
{
1
,
2
,
…
,
n
}
→
{
1
,
2
,
…
,
n
}
such that
π
(
π
(
k
)
)
≡
m
k
(
m
o
d
n
)
\pi(\pi(k)) \equiv m k(\bmod n)
π
(
π
(
k
))
≡
mk
(
mod
n
)
for all
k
∈
{
1
,
2
,
…
,
n
}
k \in\{1,2, \ldots, n\}
k
∈
{
1
,
2
,
…
,
n
}
.
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