insert random unique value and between 1 and 3000 sql server

insert unique value and between 1 and 3000 sql server

declare @st int=1
declare @rn int
while(@st <= 3000)
 begin
 set @rn=  ABS(Checksum(NewId()) % 3000);
 set  @st = @st+1;
 insert into HumanResourceSchema.Employee (EmpNo,EmpFname,EmpLname,DeptNo)values(@rn,'Smith','Jane','d1')
 end

Violation of UNIQUE KEY constraint 'c3'. Cannot insert duplicate key in object 'HumanResourceSchema.Employee'. The duplicate key value is (<NULL>)