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One and only (Posted on 2016-04-28)

There is only one prime p such that p! is p digits long.

Find it and prove its uniqueness.

See The Solution Submitted by Ady TZIDON

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re: spoiler

Comment 4 of 4 |

(In reply to spoiler by xdog)

25! has 26 digits and 25 is not prime.

Only 23 works, without qualification.

Posted by Charlie on 2016-04-28 10:39:05

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