Changeing Sequence

All,

I have a table "mytable_id_seq" that looks like so.

sequence_name | last_value | increment_by | max_value |
min_value | cache_value | log_cnt | is_cycled | is_called
----------------------+------------+--------------+---------------------+---
--------+-------------+---------+-----------+-----------
mytqble_id_seq | 4 | 1 | 9223372036854775807 |
1 | 1 | 30 | f | t

I have data that must be entered into the table "mytable" with pre-defined
ids (i.e. 1,3,5,7,25). Is it possible to change the sequence to start at
"26" the last value of the previous data?

Please tell me YES! I get an error: "ERROR: You can't change sequence
relation t_staff_staff_id_seq"

Any Help would be great!

Thanks,
-pete