1997 JBMO Problems/Problem 5

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Problem

Let $n_1$, $n_2$, $\ldots$, $n_{1998}$ be positive integers such that \[n_1^2 + n_2^2 + \cdots + n_{1997}^2 = n_{1998}^2.\] Show that at least two of the numbers are even.

Solution

See also

1997 JBMO (ProblemsResources)
Preceded by
Problem 4
Followed by
Last Problem
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All JBMO Problems and Solutions