Response to: How to use NOT IN operator

Revision 5
While Shanalal Kasims solution is cool, it doesn't work when you have a larger gap in the sequence.
This is pure SQL and should work for all cases:

WITH M AS (
    SELECT  Max(SEQUENCE) s
    FROM    table1
    WHERE   id = 1
    )
,numbers(n) AS
    (
    SELECT 1 AS n
    UNION ALL
    SELECT n + 1
    FROM Numbers,m
    WHERE n + 1 <= s
)
SELECT  n
FROM    numbers
WHERE   n NOT IN (SELECT SEQUENCE FROM table1 WHERE id = 1)