"ownership" of sequences, pseudo random unique id

I've

create table pr(
  code varchar(16) primary key,
  ...
);
create sequence pr_code_seq owned by pr.code; -- uh!

pr.code will *mostly* be obtained as

to_hex(feistel_encrypt(nextval('pr_code')))
and sometimes 'manually' inserting unique codes.

actually stuff like:
alter table pr drop column code;
or just
drop table pr

seems to work as expected (they drop the sequence too).

Should I be concerned of anything since it looks like a hack?

--
Ivan Sergio Borgonovo
http://www.webthatworks.it