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2018-IMOC
N4
N4
Part of
2018-IMOC
Problems
(1)
0 < a_{n+1} - a_n \leq 2001
Source: Vietnam TST 2001 for the 42th IMO, problem 6
6/26/2005
Let a sequence
{
a
n
}
\{a_n\}
{
a
n
}
,
n
∈
N
∗
n \in \mathbb{N}^{*}
n
∈
N
∗
given, satisfying the condition
0
<
a
n
+
1
−
a
n
≤
2001
0 < a_{n+1} - a_n \leq 2001
0
<
a
n
+
1
−
a
n
≤
2001
for all
n
∈
N
∗
n \in \mathbb{N}^{*}
n
∈
N
∗
Show that there are infinitely many pairs of positive integers
(
p
,
q
)
(p, q)
(
p
,
q
)
such that
p
<
q
p < q
p
<
q
and
a
p
a_p
a
p
is divisor of
a
q
a_q
a
q
.
algebra unsolved
algebra
number theory
pen