We have nonzero integers such that every one of them is divisible by the sum of the other numbers. Show that the sum of the numbers is precisely .
Solution
Let these numbers be and is the sum of these numbers. For every , we have , which means . Suppose that , without the loss of generality, . We investigate two cases
* If such that then so .
* for all . Let be the smallest of . We have , so .
Hence, is impossible, which means .
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