Friday, September 8, 2017

Numbers such that 7 is the smallest decimal digit of their squares.

9949370777987917 is the smallest number whose square has as its smallest decimal digit 7.
Note that $9949370777987917^2 = 98989978877879888789778997998889$. What is the next such number?
Posted by Chai Wah Wu at 11:28 PM

2 comments:

  1. MFHNovember 15, 2017 at 9:22 AM

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  2. MFHNovember 15, 2017 at 9:23 AM

    Yes, this is really remarkable. And in addition, it is prime! Maybe it is even the only such number?!

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