Random Numbers Generation, No Repeats

I'm trying to write a code that will generate random numbers and no number appears more than onece.


For I = 0 To 3
For J = 0 To I
Do
n = Int(4 * Rnd) + 1 'random number generated
Array1(I) = n 'random number settled in an array
If (I = I - J) Then 'checking for the same place in array
numsOK = True
Else
If Array1(I) = Array1(I - J) Then ' comparing two different places in an array
numsOK = False
Else
numsOK = True
End If
End If

Loop Until numsOK = True
Next J
Next I