FUNCTION factorial$ (num)
    LET f$ = ""
    LET x$ = ""
    IF num = 1 THEN LET f$ = "1"
    LET fct = 2
    DO WHILE fct <= num
       IF MOD(num, fct) = 0 THEN
          LET f$ = f$ & x$ & STR$(fct)
          LET x$ = " x "
          LET num = num / fct
       ELSE
          LET fct = fct + 1
       END IF
    LOOP
    LET factorial$ = f$
END FUNCTION

FOR i = 1 TO 20
    PRINT i; "= "; factorial$(i)
NEXT i
END