With this much variation in autonumbering, be prepared to do some work when you move from system to system. Check your documentation for information in these areas:
Specifying datatypes and other column properties (null/not null, for example)
Setting the start number and increment value
Relating the sequence element to table constraints and indexes
Locating the current highest number
Creating ranges or maximums
Dealing with DELETEs and UPDATEs (reuse the number or leave a gap?)
Most SQL engines have a rich set of tools to manage the sequential numbers.