For Non MACRO usage, I've tried a formula:
req:-
create a array of alphabets "A to Z" and 10 numerals in a 6 by 6 grid (i pu
the grid from cells f7 to k12.
then i put:
=INDIRECT(CHAR(MOD(LEFT(RAND()*10,1),6)+6+64)&(MOD(LEFT(RAND()*10,1),6)+7))
to generate a single alphanumeric character.
you can concatenate the complete formula to gerate more digits.
so for 3 digit no generation, it will be
=INDIRECT(CHAR(MOD(LEFT(RAND()*10,1),6)+6+64)&(MOD(LEFT(RAND()*10,1),6)+7))
&
INDIRECT(CHAR(MOD(LEFT(RAND()*10,1),6)+6+64)&(MOD(LEFT(RAND()*10,1),6)+7))
&
INDIRECT(CHAR(MOD(LEFT(RAND()*10,1),6)+6+64)&(MOD(LEFT(RAND()*10,1),6)+7))
spaces in between are only for clarity.