#Mathematica
f[x_]:= (* f of x defined *)
x f[x-1] (* x times f of x less 1 *)
f[1]=1 (* Mogami River *)
Pedants may read the last line as "f of 1 is 1", but I couldn't resist the shout-out to Basho.
###Testing:
Table[f[n], (* Table f of n *)
{n, 1, 10, 1}] (* n from 1 to 10 by 1 *)
ListLogPlot[%] (* ListLogPlot output *)
###Returning:
(1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800)
###Linguistic Distinctiveness Bonus Haiku (inspired by @cormullion)
Rewrite any term
High-level functions abound —
Mathematica