Missing values from a sequence generated column

If we have a column that is a sequence generated value column from a table we can get holes in the values (due to several issues that are common known).
Here is a code that shows that holes using as example a table named my_table and a column id

SELECT id,
       next_id,
       DECODE (next_id, id + 1, '',
                        DECODE (id + 1, next_id - 1, TO_CHAR (id + 1),
                                        TO_CHAR (id + 1)
                                        || '-'
                                        || TO_CHAR (next_id - 1)))
       missing_values
FROM   (SELECT id,
               LEAD (id, 1) over (ORDER BY id) AS next_id
        FROM   my_table)
WHERE  next_id IS NOT NULL
   AND DECODE (next_id, id + 1, '',
                        DECODE (id + 1, next_id - 1, TO_CHAR (id + 1),
                                        TO_CHAR (id + 1)
                                        || '-'
                                        || TO_CHAR (next_id - 1))) IS NOT NULL

An example of the output:

22     42     23-41
42     44     43
44     46     45
46     62     47-61
62     64     63
64     68     65-67