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David Meyer (dmm@mathstodon.xyz)'s status on Friday, 15-Dec-2023 00:42:57 JST David Meyer

A factorion is an interesting kind of natural number that equals the sum of the factorials of its decimal digits [1,3].
40585 is the largest known factorion and was discovered in 1964 by Leigh Janes [2].
#factorion #math #maths #numbertheory
References
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[1] "Factorion", https://en.wikipedia.org/wiki/Factorion
[2] "Mathematician:Leigh Janes", https://proofwiki.org/wiki/Mathematician:Leigh_Janes
[3] "Factorion", https://mathworld.wolfram.com/Factorion.html
In conversation about a year ago from mathstodon.xyz permalink
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1. A factorion is an interesting kind of natural number that equals the sum of the factorials of its decimal digits [1]. 40585 is the largest known factorion and was discovered in 1964 by Leigh Janes [2]. #factorion #math #maths References -------------- [1] "Factorion", https://en.wikipedia.org/wiki/Factorion [2] "Mathematician:Leigh Janes", https://proofwiki.org/wiki/Mathematician:Leigh_Janes
  https://media.mathstodon.xyz/media_attachments/files/111/579/042/341/966/223/original/f8b9a6e5f5fad333.jpeg
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  Factorion
  
  In number theory, a factorion in a given number base b {\displaystyle b} is a natural number that equals the sum of the factorials of its digits. The name factorion was coined by the author Clifford A. Pickover. Definition Let n {\displaystyle n} be a natural number. For a base ...
3. No result found on File_thumbnail lookup.
  
  Mathematician:Leigh Janes - ProofWiki
4. Domain not in remote thumbnail source whitelist: mathworld.wolfram.com
  
  Factorion -- from Wolfram MathWorld
  
  from Weisstein, Eric W.
  
  A factorion is an integer which is equal to the sum of factorials of its digits. There are exactly four such numbers: 1 = 1! (1) 2 = 2! (2) 145 = 1!+4!+5! (3) 40585 = 4!+0!+5!+8!+5! (4) (OEIS A014080; Gardner 1978, Madachy 1979, Pickover 1995). Obviously, the factorion of an n-digit number cannot exceed n·9!.

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