The book is now available! 81
(another Prime Pages' Curiosity)
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81 = (prime(8)+8) * (prime(1)+1). Note that 81 is the only known number (less than 10000000) with this property. [Firoozbakht]


  Submitted: 2004-09-21 10:55:09;   Last Modified: 2011-08-01 12:35:03.

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