Run this as sys as sysdba.

Code:
CREATE TABLE SEQ$
(
  OBJ#        NUMBER                            NOT NULL,
  INCREMENT$  NUMBER                            NOT NULL,
  MINVALUE    NUMBER,
  MAXVALUE    NUMBER,
  CYCLE#      NUMBER                            NOT NULL,
  ORDER$      NUMBER                            NOT NULL,
  CACHE       NUMBER                            NOT NULL,
  HIGHWATER   NUMBER                            NOT NULL,
  AUDIT$      VARCHAR2(38)                      NOT NULL,
  FLAGS       NUMBER
)
TABLESPACE SYSTEM
PCTUSED    40
PCTFREE    10
INITRANS   1
MAXTRANS   255
STORAGE    (
            INITIAL          64K
            MINEXTENTS       1
            MAXEXTENTS       2147483645
            PCTINCREASE      0
            FREELISTS        1
            FREELIST GROUPS  1
            BUFFER_POOL      DEFAULT
           )
LOGGING 
NOCACHE
NOPARALLEL;


CREATE UNIQUE INDEX I_SEQ1 ON SEQ$
(OBJ#)
LOGGING
TABLESPACE SYSTEM
PCTFREE    10
INITRANS   2
MAXTRANS   255
STORAGE    (
            INITIAL          64K
            MINEXTENTS       1
            MAXEXTENTS       2147483645
            PCTINCREASE      0
            FREELISTS        1
            FREELIST GROUPS  1
            BUFFER_POOL      DEFAULT
           )
NOPARALLEL;