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Problems
Contests
National and Regional Contests
China Contests
(China) National High School Mathematics League
2021 China Second Round A2
4
4
Part of
2021 China Second Round A2
Problems
(1)
number theory problem
Source: 2021 China Second Round A2
2/23/2023
The positive integer formed after writing
k
k
k
consecutive positive integers from smallest to largest is called a
k
−
continuous
k-\text{continuous}
k
−
continuous
number. For example
99100101
99100101
99100101
is a
3
−
continuous
3-\text{continuous}
3
−
continuous
number. Prove that: for
∀
N
\forall N
∀
N
,
k
∈
Z
+
k\in\mathbb Z^+
k
∈
Z
+
, there must be a
k
−
continuous
k-\text{continuous}
k
−
continuous
number that can be divisible by
N
N
N
.
number theory