"Paul Black" wrote:
I would like to generate unique random numbers from say 34
numbers, and starting in "B2" list them in 5 number
combinations going down until ALL the 34 numbers have been
used. I know in this example the first 6 combinations will
have 5 numbers and the 7th combination will have only 4.
There may be occassions where there might be more or less
numbers than 34 numbers and maybe 4,5,6 or 7 number
combinations

See the UDF below. Use as you would RANDBETWEEN, e.g.
=uniqRandBetween(1,34).

Each uniqRandBetween range has its own pool of unique random numbers. So
two calls to uniqRandBetween(1,34) will generate a unique pair of numbers;
but a call to uniqRandBetween(1,34) and uniqRandBetween(1,20) might result
in the same random number.

As currently configured, uniqRandBetween supports up to 10 different ranges,
each with a maximum range of 100 values (hi - lo + 1). Change the Const
variable maxNTabl and maxN as needed.

To enter the UDF, in Excel, press alt+F8 to open the VBA window. In VBA,
click on Insert, then Module to open a VBE pane. Copy the text of the UDF
below and paste it into the VBE pane. You can now close the VBA window.

The UDF....

Option Explicit

Function uniqRandBetween(lo As Long, hi As Long)

'***** customize *****
' maxNtabl = number of lo-to-hi ranges
' maxN = max size of range, hi-lo+1
'******
Const maxNtabl As Long = 10
Const maxN As Long = 100

Static tabl(1 To maxNtabl, 1 To 3 + maxN) As Long
Static ntabl As Long
Dim t As Long, n As Long, x As Long

' find table for lo-to-hi range

If lo hi Then GoTo retnError
For t = 1 To ntabl
If tabl(t, 1) = lo And tabl(t, 2) = hi Then GoTo continue
Next
If ntabl = maxNtabl Then GoTo retnError
If hi - lo + 1 maxN Then GoTo retnError
ntabl = ntabl + 1
t = ntabl
tabl(t, 1) = lo
tabl(t, 2) = hi
tabl(t, 3) = 0

continue:

' generate list of random numbers, if needed

n = tabl(t, 3)
If n = 0 Then
For n = 1 To hi - lo + 1
tabl(t, 3 + n) = lo + n - 1
Next
n = n - 1
End If

' generate unique random number.
'
' note: you might want to change Rnd to
' Evaluate("RAND()") to use Excel RAND.
' slower, but more maybe robust.

x = 1 + Int(n * Rnd)
uniqRandBetween = tabl(t, 3 + x)
If x < n Then tabl(t, 3 + x) = tabl(t, 3 + n)
tabl(t, 3) = n - 1
Exit Function

retnError:

uniqRandBetween = CVErr(xlErrValue)
End Function