/*
 * @(#)$Id: fac,v 1.1 1995/05/15 17:31:25 img Exp $
 *
 * $Log: fac,v $
 * Revision 1.1  1995/05/15 17:31:25  img
 * 	* factorial
 *
 */

fac(n) <==> p_ind(n,s(0),[p,r,times(s(p),r)]).
