MathDB
Problems
Contests
International Contests
IMO Longlists
1972 IMO Longlists
23
23
Part of
1972 IMO Longlists
Problems
(1)
2n digit number such that a_{2n} ... a_1 = (a_n ... a_1)^2
Source:
12/6/2010
Does there exist a
2
n
2n
2
n
-digit number
a
2
n
a
2
n
−
1
⋯
a
1
‾
\overline{a_{2n}a_{2n-1}\cdots a_1}
a
2
n
a
2
n
−
1
⋯
a
1
(for an arbitrary
n
n
n
) for which the following equality holds:
a
2
n
⋯
a
1
‾
=
(
a
n
⋯
a
1
‾
)
2
?
\overline{a_{2n}\cdots a_1}= (\overline{a_n \cdots a_1})^2?
a
2
n
⋯
a
1
=
(
a
n
⋯
a
1
)
2
?
number theory unsolved
number theory