SQL & PL/SQL

Hello,

I want to generate a string 'ABC', concatenated with a sequence my_seq

CREATE SEQUENCE CONTURI_EXTERNE_SEQ
  START WITH 1
  MINVALUE 1
  MAXVALUE 9999999999
  NOCYCLE
  CACHE 20
  NOORDER;

, and to pad the resulting string from left to right, until the length of the sequence.. e.g. the max. sequence length here is 9, so first I should generate ABC000000001, and after 99 numbers, ABC000000100.

Is it possible to do this in a single expression, and with sequences?

If I have had a simple number, that was simple, but using a sequence?

Oracle Database 11.2.0.2.

Thank you!