D.2.2.6 factorial

Procedure from library general.lib (see general_lib).

Usage:

factorial(n[,p]); n,p integers

Return:

factorial(n): n! (computed in characteristic 0), of type string.
factorial(n,p): n! computed in characteristic 0 or prime(p)
- of type number if a basering is present and 0=p=char(basering) or if prime(p)=char(basering)
- of type string else

Example:

LIB "general.lib";
factorial(37);"";                 //37! of type string (as long integer)
→ 13763753091226345046315979581580902400000000
→ 
ring r1 = 0,x,dp;
number p = factorial(37,0);       //37! of type number, computed in r
p;
→ 13763753091226345046315979581580902400000000

See also: prime.