[PD] weird behavior of factorial in expr

[oscar pablo di liscia]

Hello list:
I apologize if this is already a very well known issue, but i've found that
the "fact" (factorial) function does not seem to work properly in the
"expr" external when called with an argument greater than 12.
I attached a patch in which i've made my own abstraction (which I cannot
tell it is done  in the most efficient way, but matches the result of any
calculator) to show the discrepancy. Am I doing something wrong?

Oscar Pablo Di Liscia
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