Table with identity column in merge replication
When using Merge with identity columns — will need to specify an identity range management option of either automatic or manual so that duplicates do not occur.

With automatic, replication will automatically manage the assignment of identity ranges for nodes participating in the Merge topology.

With manual, you will need to manually assign "islands" of ranges for nodes using DBCC CHECKIDENT.

Have a look at Replicate Identity Columns.