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PAMO Problem 6: Binomial coefficient not divisible by 5
Source: 2019 Pan-African Mathematics Olympiad, Problem 6
4/9/2019
Find the
2019
2019
2019
th strictly positive integer
n
n
n
such that
(
2
n
n
)
\binom{2n}{n}
(
n
2
n
)
is not divisible by
5
5
5
.
binomial coefficients
PAMO
number theory