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15
2012-2013 Winter OMO #15
2012-2013 Winter OMO #15
Source:
January 16, 2013
Online Math Open
Problem Statement
A permutation
a
1
,
a
2
,
.
.
.
,
a
13
a_1, a_2, ..., a_{13}
a
1
,
a
2
,
...
,
a
13
of the numbers from
1
1
1
to
13
13
13
is given such that
a
i
>
5
a_i > 5
a
i
>
5
for
i
=
1
,
2
,
3
,
4
,
5
i=1,2,3,4,5
i
=
1
,
2
,
3
,
4
,
5
. Determine the maximum possible value of
a
a
1
+
a
a
2
+
a
a
3
+
a
a
4
+
a
a
5
.
a_{a_1} + a_{a_2} + a_{a_3} + a_{a_4} + a_{a_5}.
a
a
1
+
a
a
2
+
a
a
3
+
a
a
4
+
a
a
5
.
Evan Chen
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