Newbie question: Autonumber

How can i create a coloumn in a table, that has an autogenerated uniqe number? Im connecting to a Oracle 8i server

CREATE TABLE EMPLOYEE(
    EmployeeNr AUTONUMBER NOT NULL,
    Name VARCHAR2(50),
CONSTRAINT EmployeeNr_pk PRIMARY KEY(EmployeeNr));

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Eirik Eldorsen