Tables with names that begin with the pound sign (#) are temporary tables. You cannot create other types of objects with names that begin with the pound sign.
The SAP ASE server performs special operations on temporary table names to maintain unique naming on a per-session basis. When you create a temporary table with a name of fewer than 238 bytes, the sysobjects name in the tempdb adds 17 bytes to make the table name unique. If the table name is more than 238 bytes, the temporary table name in sysobjects uses only the first 238 bytes, then adds 17 bytes to make it unique.
In versions of SAP ASE earlier than 15.0, temporary table names in sysobjects were 30 bytes. If you used a table name with fewer than 13 bytes, the name was padded with underscores ( _ ) to 13 bytes, then another 17 bytes of other characters to bring the name up to 30 bytes.