Hello,

I suggest:

1. Take my function UniqRandInt() from www.sulprobil.com
2. Put at least 35 different characters of your choice into A1:A35 (because
35*351200). More won't hurt. Leave rest of column A empty.
3. Enter into B1:
=COUNTA(A:A)
4. Select the 1200 cells C1:C1200 and enter as array formula (CTRL + SHIFT +
ENTER):
=uniqrandint(B1*B1)
5. Enter into D1:
=INDEX(A:A,1+INT(C1/B$1))&INDEX(A:A,1+MOD(C1,B$1))
and copy down to D1200

HTH,
Bernd