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Odd digited square (Posted on 2019-06-02)

Find all natural numbers n such that n² has only odd digits.

No Solution Yet Submitted by Danish Ahmed Khan

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Consider the squares mod 100

{00, 01, 04, 09, 16, 21, 24, 25, 29, 36, 41, 44, 49, 56, 61, 64, 69, 76, 81, 84, 89, 96}

All have at least one even component.

So the only natural numbers n such that n^2 has only odd digits are 1 and 3.

Edited on June 2, 2019, 10:05 am

Posted by broll on 2019-06-02 08:25:09

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