Factorial Type Functions

**Factorial**- in mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example,
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**Hyperfactorials**-
Occasionally the hyperfactorial of n is considered. It is written as H(n) and defined by
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**Multifactorials**- A common related notation is to use multiple exclamation points to denote a multifactorial, the product of integers in steps of two (n!!), three (n!!!)...click here to read more.

**Primorials**-
In mathematics, and more particularly in number theory, primorial is a function from natural numbers to natural numbers similar to the factorial function, but rather than ...click here to read more.

**Quadrupal factorials**- The so-called quadruple factorial, however, is not the multifactorial n!(4); it is a much larger number given by (2n)!/n!, starting as...click here to read more.

**Superfactorials**-
Neil Sloane and Simon Plouffe defined a superfactorial in The Encyclopedia of Integer Sequences (Academic Press, 1995) to be the product of the...click here to read more.