run a package on the 15th of each month.

hello
I have a job I ouuld like to submit to delete historical data. I need the job to run the 15th of every month at 330 am. I am not sure how to get the date right ( IE the 15th)for the Interval parm I need to pass w/ the DBMS_JOB.SUBMIT function.

 DBMS_JOB.SUBMIT(v_JobNum,     -- Return of job number
        'PA_SSA_FELONREC_LOAD.SP_INSERT_EVSFUFEL;',
        v_run_date,            -- Next date/time to run


        -- Interval   if null dont run but once

        -- this will set the run to the 15 of each month