Using nextval(seq) in more than one column

I am trying to design some tables that have keys that look like:

ASDF-####

where #### should be derived from a sequence.  However, I would like the
primary key to be an integer for speed of indexing, etc.  I don't see a
way using standard DDL followed by inserts to have the #### be the same
number as the integer primary key.  Is that the case?

In other words, I would like the rows to look like:

1   ASDF-1   ....
2   ASDF-2   ....

Thanks,
Sean