Is there a way to get pg_dump to exclude a specific sequence?

There are two cases:

  1. The sequence to exclude is owned by a table you're also dumping (typical case: SERIAL column).
    See: Dump a table without sequence table in postgres
    Short answer: no, the sequence can't be left aside.

  2. The sequence is not owned by a dumped table. Then it can be excluded with the --exclude-table switch as if it was a table.

From pg_dump documentation:

-T table --exclude-table=table

Do not dump any tables matching the table pattern.

The pattern is interpreted according to the same rules as for -t

And about -t:

-t table
--table=table

Dump only tables (or views or sequences or foreign tables) matching table

If the sequence is owned by a table you can exclude both the sequence and the table using -T, such as:

pg_dump -T table -T table_id_seq