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Sum of subfactorials (Posted on 2018-02-25)

What is the only number equal to the sum of subfactorials of its digits?

Hint: it is below 150000

This fact was discovered by Malachy in 1979.

See The Solution Submitted by Ady TZIDON

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about Madachy

| Comment 2 of 3 |

Better late than never: it is MADACHY, not Malachy.

Joseph Steven Madachy ( 1927 �" 2014) was a research chemist, technical editor and renowned recreational mathematician. He was the lead editor of Journal of Recreational Mathematics for about 30 years.

Edited on April 15, 2018, 10:24 am

Posted by Ady TZIDON on 2018-02-28 05:38:13

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