How to fill an array with different random numbers from 1000 to 9999 using PASCAL

I'm trying to fill an array with different numbers from 1000 to 9999. My problem is that my code is filling the array with the same number, here is my approach :

repeat
    write('Enter an Integer from 5 to 20: '); readln(n)
until (n in [5..20]);

for i:=1 to n do 
begin
    T[i]:=random(9000)+1000; // 1000 to 9999
    randomize
end;

writeln('___________________________________');
for i:=1 to n do 
    write(T[i], ' | '  );
writeln;    
writeln('___________________________________');