Azeppo.107
net.general
utzoo!decvax!ucbvax!mhtsa!harpo!zeppo!raj
Mon Jan 25 09:48:09 1982
Factorial Query
	Concerning the question why 0! is defined to be 1,
there is another reason.  Anyone who has taken probability
theory has learned that the formula which gives the number
of combinations of n objects taken k at a time is n!/k!(n-k)!
For the case when k=n, the formula should give the result 1,
which makes it necessary for 0! to be 1.

					zeppo!raj