Description:I used the below script to Schedule the job the Every Sunday 3 AM.
Script:#### Script Starts Here ####
VARIABLE jobno NUMBER;
BEGIN
DBMS_JOB.SUBMIT(:jobno, 'SCHEMANAME.PACKAGENAME.PROCEDURENAME;', TRUNC(NEXT_DAY(SYSDATE,'SUNDAY'))+3/24,'TRUNC(NEXT_DAY(SYSDATE,''SUNDAY''))+3/24 ');
COMMIT;
END;
/
#### Script Ends Here ####