It's probably not a coincidence that every value ( with the exception of the first two) is the previous + 5 and that you have a clause "CACHE 5" in your sequence. This is what Oracle( I assume it's ORACLE you're using) documentation says about the CACHE clause:
Quote:
CACHE Specify how many values of the sequence Oracle preallocates and keeps in
memory for faster access. This integer value can have 28 or fewer digits. The
minimum value for this parameter is 2. For sequences that cycle, this value must be
less than the number of values in the cycle. You cannot cache more values than will
fit in a given cycle of sequence numbers. Therefore, the maximum value allowed for
CACHE must be less than the value determined by the following formula:
(CEIL (MAXVALUE - MINVALUE)) / ABS (INCREMENT)
If a system failure occurs, all cached sequence values that have not been used in
committed DML statements are lost. The potential number of lost values is equal to
the value of the CACHE parameter.
Are you sure you didn't have any system failures?