The need to know if a field is using/connected to a sequence

I currently use this to get field information of a table:
Now I just want to know (boolean field maby??) if a field is using/connected
to q sequence or not.
Which table should I access to get this information


SELECT
a.attnum,
a.attname AS field,
t.typname AS type,
a.attlen AS length,
a.atttypmod AS lengthvar,
a.attnotnull AS notnull
FROM
pg_class c,
pg_attribute a,
pg_type t
WHERE
c.relname = 'your_table_name'
and a.attnum > 0
and a.attrelid = c.oid
and a.atttypid = t.oid
ORDER BY a.attnum