The trienn[1]) is equal to \(\lbrace9,9,9\rbrace\) or \(9\lbrace9\rbrace9\) in BEAF or 9 hendecated to 9.[2] The term was coined by Jonathan Bowers. This is the ninth Ackermann number.


The name of this number is based on Greek prefixes tri- (three) and ennea- (nine), meaning that there are 3 9's in the array.

Sources Edit

  1. Template:Citation/CS1
  2. Template:Citation/CS1
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