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INAMO 2019 Problem 01
Source: Indonesia Mathematical Olympiad (INAMO) 2019 Problem 01
7/2/2019
Given that
n
n
n
and
r
r
r
are positive integers. Suppose that
1
+
2
+
⋯
+
(
n
−
1
)
=
(
n
+
1
)
+
(
n
+
2
)
+
⋯
+
(
n
+
r
)
1 + 2 + \dots + (n - 1) = (n + 1) + (n + 2) + \dots + (n + r)
1
+
2
+
⋯
+
(
n
−
1
)
=
(
n
+
1
)
+
(
n
+
2
)
+
⋯
+
(
n
+
r
)
Prove that
n
n
n
is a composite number.
number theory
primes