Factorial
n!
returns the factorial of n
.
Attributes[Factorial] := {Listable, NumericFunction, Protected, ReadProtected}
Simple examples
In[1]:= Factorial[20] Out[1]= 2432902008176640000
In[2]:= Factorial[5] Out[2]= 120
Further examples
In[1]:= Factorial[0] Out[1]= 1
In[2]:= Factorial[-1] Out[2]= ComplexInfinity