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Author: mathforces
Problem has been solved: 61 times

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Let $ T =\{x \in N | 10 \nmid x\} $. A function $ f: T \to T $ is given such that $ f (x) $ is obtained from $ x $ by rearranging all the digits $ x $ in the reverse order. A number $ a$ is called $beautiful $ if $ f (a^2) = f (a)^2 $ and $ f (a) \neq a $. Find the sum of all two-digit $ beautiful $ numbers.





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