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1998 Polish MO Finals
1
infinitely many muplitples of 7 in a sequence
infinitely many muplitples of 7 in a sequence
Source:
November 11, 2005
number theory unsolved
number theory
Problem Statement
Define the sequence
a
1
,
a
2
,
a
3
,
.
.
.
a_1, a_2, a_3, ...
a
1
,
a
2
,
a
3
,
...
by
a
1
=
1
a_1 = 1
a
1
=
1
,
a
n
=
a
n
−
1
+
a
[
n
/
2
]
a_n = a_{n-1} + a_{[n/2]}
a
n
=
a
n
−
1
+
a
[
n
/2
]
. Does the sequence contain infinitely many multiples of
7
7
7
?
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