Best way to create a sequence generator at run time?

Hi all,

I am trying to write plpgsql that must create a sequence generators during runtime.  The min/max values are provided as
functionparameters. 

The following isn't working for me and I'm not too surprised, but not sure of the best way to proceed.  I am guessing I
needto use PERFORM, EXECUTE or cursors or something? 

==
create or replace function my_number_assigner(
    p_floor int,
    p_ceiling int
) returns void as
$$
    create sequence num_generator minvalue p_floor maxvalue p_ceiling start with p_floor;
end
$$
language plpgsql;
==

 ERROR:  syntax error at or near "$1"
LINE 1: create sequence num_generator minvalue  $1  maxvalue  $2  s...
                                                 ^
QUERY:  create sequence num_generator minvalue  $1  maxvalue  $2  start with  $1
CONTEXT:  SQL statement in PL/PgSQL function "my_number_assigner" near line 35

I presume that the create sequence expression wants to see literals instead of variables, right?  I knew I was going to
runinto this situation sooner or later.  What should I be doing here? 

- Leon