Problem Statement

The factorial of a number, written as

n !

{\displaystyle n!}

, is defined as

n !

n ( n − 1 ) ( n − 2 ) . . . ( 2 ) ( 1 )

{\displaystyle n!=n(n-1)(n-2)...(2)(1)}

. Multifactorials generalize factorials as follows: In all cases, the terms in the products are positive integers. If we define the degree of the multifactorial as the difference in successive terms that are multiplied together for a multifactorial (the number of exclamation marks), then the task is twofold:

Note: The wikipedia entry on multifactorials gives a different formula. This task uses the Wolfram mathworld definition.

Let's start with the solution:

            NORMAL MODE IS INTEGER
            
            INTERNAL FUNCTION(N,DEG)
            ENTRY TO MLTFAC.
            RSLT = 1
            THROUGH MULT, FOR MPC=N, -DEG, MPC.L.1
MULT        RSLT = RSLT * MPC
            FUNCTION RETURN RSLT
            END OF FUNCTION
            
            THROUGH SHOW, FOR I=1, 1, I.G.10
SHOW        PRINT FORMAT OUTP, MLTFAC.(I,1), MLTFAC.(I,2), 
          0      MLTFAC.(I,3), MLTFAC.(I,4), MLTFAC.(I,5)
           
            VECTOR VALUES OUTP = $5(I10,S1)*$
            END OF PROGRAM