Get the Deleted ids from auto-increment column in a database

This is query to get the deleted record ids from a table

SELECT (t1.id +1) AS gap_starts_at, (SELECT MIN( t3.id ) -1 FROM contacts t3 WHERE t3.id > t1.id) AS gap_ends_at FROM contacts t1 WHERE NOT EXISTS (SELECT t2.id FROM contacts t2 WHERE t2.id = t1.id +1) HAVING gap_ends_at IS NOT NULL  ORDER BY t1.id LIMIT 0 , 30


OR


SELECT l.id +1 AS 
START 
FROM contacts AS l
LEFT OUTER JOIN contacts AS r ON l.id +1 = r.id

WHERE r.id IS NULL order by l.id