MathDB
Problems
Contests
International Contests
IMO Longlists
1974 IMO Longlists
20
Finding n such that sum of a_i^-2 is 1 [ILL 1971]
Finding n such that sum of a_i^-2 is 1 [ILL 1971]
Source:
January 2, 2011
algebra proposed
algebra
Problem Statement
For which natural numbers
n
n
n
do there exist
n
n
n
natural numbers
a
i
(
1
≤
i
≤
n
)
a_i\ (1\le i\le n)
a
i
(
1
≤
i
≤
n
)
such that
∑
i
=
1
n
a
i
−
2
=
1
\sum_{i=1}^n a_i^{-2}=1
∑
i
=
1
n
a
i
−
2
=
1
?
Back to Problems
View on AoPS