SQL> create table test21
  2  (id number primary key,
  3  name varchar2(10));

Table created.

SQL> create sequence test21_seq
  2  start with 1 
  3  increment by 1;

Sequence created.

SQL> insert into test21 values
  2  (test21_seq.nextval, '&name');
Enter value for name: 1name
old   2: (test21_seq.nextval, '&name')
new   2: (test21_seq.nextval, '1name')

1 row created.

SQL> /
Enter value for name: 2name
old   2: (test21_seq.nextval, '&name')
new   2: (test21_seq.nextval, '2name')

1 row created.

SQL> /
Enter value for name: 3name
old   2: (test21_seq.nextval, '&name')
new   2: (test21_seq.nextval, '3name')

1 row created.

SQL> select * from test21;

        ID NAME
---------- ----------
         1 1name
         2 2name
         3 3name