factorial

You are here: irt.org | FOLDOC | factorial

<mathematics> The mathematical function that takes a natural number, N, and returns the product of N and all smaller positive integers. This is written

	N! = N * (N-1) * (N-2) * ... * 1.

The factorial of zero is one because it is an empty product.

Factorial can be defined recursively as

	0! = 1
	N! = N * (N-1)!		, N > 0

The gamma function is the equivalent for real numbers.

For example, the number of ways of shuffling 52 playing cards is 52! or nearly 10^68. 52 Factorial (http://czep.net/weblog/52cards.html).

(2012-11-23)

Nearby terms: FACT « fact « factor « factorial » FAD » failback » failover

FOLDOC, Topics, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, ?, ALL