How to find which sequence name is used in a table - Redux

Question

(The other thread was locked before I could respond, so I'm posting this here as a non-question.)
Beginning with 12c, there is now a way to associate a sequence with a table.  It's a new feature called an Identity column.
create table t
(some_id number generated as identity --< creates a system generated sequence
,name varchar2(30)
insert into t (name) values ('Smith');
insert into t (name) values ('Jones');
insert into t (name) values ('Anderson');
commit;
select * from t;
        SOME_ID NAME
              1 Smith
              2 Jones
              3 Anderson
select table_name, column_name, data_default from user_tab_columns where table_name = 'T' and column_name = 'SOME_ID';
TABLE_NAME COLUMN_NAME DATA_DEFAULT
T          SOME_ID     "C##SELSE"."ISEQ$$_91955".nextval
select * from user_sequences;
SEQUENCE_NAME
ISEQ$$_91955

Answer 1

There's nothing stopping you from using the generated sequence for something else, however you can NOT override it when doing an insert (as long as you've specified ALWAYS which is the default).
SQL> create table t
  2  (some_id number generated as identity
  3  ,name varchar2(30)
  4  );
Table created.
SQL> select * from user_sequences;
SEQUENCE_NAME
ISEQ$$_91970
SQL> select ISEQ$$_91970.nextval from dual;
             NEXTVAL
                   1
SQL> select ISEQ$$_91970.nextval from dual;
             NEXTVAL
                   2
SQL> insert into t values (99,'smith');
insert into t values (99,'smith')
ERROR at line 1:
ORA-32795: cannot insert into a generated always identity column