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2015 EGMO
4
4
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2015 EGMO
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(1)
EGMO P4 infinite sequence
Source: EGMO 2015, Problem 4
4/17/2015
Determine whether there exists an infinite sequence
a
1
,
a
2
,
a
3
,
…
a_1, a_2, a_3, \dots
a
1
,
a
2
,
a
3
,
…
of positive integers which satisfies the equality
a
n
+
2
=
a
n
+
1
+
a
n
+
1
+
a
n
a_{n+2}=a_{n+1}+\sqrt{a_{n+1}+a_{n}}
a
n
+
2
=
a
n
+
1
+
a
n
+
1
+
a
n
for every positive integer
n
n
n
.
number theory
Sequence
EGMO
Integer sequence
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