Factorial function

-- PL/SQL Factoral No ---
DECLARE
   fn   NUMBER;
BEGIN
   fn := :fa;
   IF fn <> 1
   THEN
      FOR i IN 1..fn LOOP
      fn:=fn*i;
      END LOOP;
      DBMS_OUTPUT.put_line (fn);
   ELSE
      DBMS_OUTPUT.put_line (fn);
   END IF;
END;
/