Find orphan sequences

-- find orphan sequences in postgresql
SELECT
  ns.nspname AS SchemaName,
  c.relname  AS SequenceName
FROM pg_class AS c
  JOIN pg_namespace AS ns
    ON c.relnamespace = ns.oid
WHERE c.relkind = 'S'
      AND NOT EXISTS(SELECT *
                     FROM pg_depend
                     WHERE objid = c.oid AND deptype = 'a')
ORDER BY c.relname;