Get all Numbers that are not existing from a Microsoft SQL-VarChar-Column

I have a table with a Column for ID-Numbers that are not increased in single steps.

So there are Numbers that are not used and this i need. The Column is a VarChar-Column.

For Example:

Used Numbers in the table = 2, 5, 7, 9, 10 etc.

So i need a Query that gives me = 1, 3, 4, 6, 8 etc.

Pseudo-Code something like:

select numbers from Table NOT IN (select numbers from table)!

I have tried with NOT IN and NOT EXISTS, but nothing works.

Can someone help me to achieve this?

EDIT: Range of Numbers is from 0 to 99999999 !!!

DECLARE @Table AS TABLE
(
    Id VARCHAR(5)
)

INSERT INTO @Table
VALUES
 ('1')
,('3')
,('5')
,('7')
,('10')

DECLARE @Range AS TABLE
(
    RangeId VARCHAR(10)
)

INSERT INTO @Range
SELECT TOP (1000000) n = CONVERT(VARCHAR(10), ROW_NUMBER() OVER (ORDER BY s1.[object_id]))
FROM sys.all_objects AS s1 CROSS JOIN sys.all_objects AS s2
OPTION (MAXDOP 1)

select 
    MissingId = RangeId
from 
    @Range AS R
    LEFT OUTER JOIN @Table AS T ON T.Id = R.RangeId
WHERE
    CONVERT(INT,R.RangeId) <= (SELECT MAX(CONVERT(INT,Id)) FROM @Table)
    AND T.Id IS NULL
order by MissingId