In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller 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. (2005-01-07)

In statistics, a full factorial experiment is an experiment whose design consists of two or more factors, each with discrete possible values or "levels", and whose experimental units take on all possible combinations of these levels across all such factors. A full factorial design may also be called a fully crossed design.

In combinatorics, the factorial number system, also called factoradic, is a mixed radix numeral system adapted to numbering permutations. It is also called factorial base, although factorials do not function as base, but as place value of digits.

A frequency plan, bandplan, band plan or wavelength plan is a plan for using a particular band of radio frequencies, that are a portion of the electromagnetic spectrum. Each frequency plan defines the frequency range to be included, how channels are to be defined, and what will be carried on those channels.

A site plan or a plot plan is a type of drawing used by architects, landscape architects, urban planners, and engineers which shows existing and proposed conditions for a given area, typically a parcel of land which is to be modified. Sites plan typically show buildings, roads, sidewalks and paths/trails, parking, drainage facilities, sanitary sewer lines, water lines, lighting, and landscaping and garden elements.

The New Jersey Plan (also known as the Small State Plan or the Paterson Plan) was a proposal for the structure of the United States Government presented during the Constitutional Convention of 1787. Principally authored by William Paterson of New Jersey, the New Jersey Plan was an important alternative to the Virginia Plan proposed by James Madison and Edmund Randolph of Virginia.

<operating system> (Named after the classically bad, exceptionally low-budget SF film "Plan 9 from Outer Space") An operating system developed at Bell Labs by many researchers previously intimately involved with Unix. Plan 9 is superficially Unix-like but features far finer control over the name-space (on a per-process basis) and is inherently distributed and scalable. Plan 9 is divided according to service functions. CPU servers concentrate computing power into large multiprocessors; file servers provide repositories for storage and terminals give each user of the system a dedicated computer with bitmap screen and mouse on which to run a window system. The sharing of computing and file storage services provides a sense of community for a group of programmers, amortises costs and centralises and hence simplifies management and administration. The pieces communicate by a single protocol, built above a reliable data transport layer offered by an appropriate network, that defines each service as a rooted tree of files. Even for services not usually considered as files, the unified design permits some simplification. Each process has a local file name space that contains attachments to all services the process is using and thereby to the files in those services. One of the most important jobs of a terminal is to support its user's customised view of the entire system as represented by the services visible in the name space. http://plan9.bell-labs.com/plan9dist/. (2005-02-15)

In mathematics, Bhargava's factorial function, or simply Bhargava factorial, is a certain generalization of the factorial function developed by the Fields Medal winning mathematician Manjul Bhargava as part of his thesis in Harvard University in 1996. The Bhargava factorial has the property that many number-theoretic results involving the ordinary factorials remain true even when the factorials are replaced by the Bhargava factorials.