What is a good choice of letters for serial numbers?
When creating serial numbers, one could use only numbers, 0
-9
. This causes serial numbers to be quite long. To save space, one could also user letters A
-Z
, resulting in shorter numbers, by a factor of 1.56 (log 36 / log 10). But this can cause trouble reading those serial numbers, since 0
and O
are quite similar. Also l
and 1
, and mayby I
and 1
, or even J
and 1
.
So a first approximation seems to be to use the digits 0123456789ABCDEFGHKMNPQRSTUVWXYZ
for serial numbers. That is 32 digits and hence serial numbers are still 1.51 times shorter than in base-10.
Is there any well-known best practice for issuing serial numbers?