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• Factorial may be defined as, for all _positive integers_ n, n! = n*(n-1)! 1! = 1*(1-1)! 1! = 1*0! 1!/1 = 0! 0! = 1 Although according to Wikipedia, "0! is explicitly defined to be 1". One application of factorial is rearran…

  in how factorial ( 0 ) = 1 ? Comment by bum June 2021
• Factorial may be defined as, for all _positive integers_ n, n! = n*(n-1)! 1! = 1*(1-1)! 1! = 1*0! 1!/1 = 0! 0! = 1 Although according to Wikipedia, "0! is explicitly defined to be 1". One application of factorial is rearran…

  in how factorial ( 0 ) = 1 ? Comment by bum May 2021