18 May
2006
18 May
'06
10:11 a.m.
On 5/17/06, Thane Plambeck <thane@best.com> wrote:
UPS tracking#: 1Z9999999999999999 This link doesn't give the checksum algorithm for the last digit, but tells what all the rest mean http://osiris.978.org/~alex/ups.html
US $20 bill, Series 2004: EB 42994244 D
Such schemes are presumably often proprietary / unpublished, for security reasons, although the "there is no security through obscurity" maxim would seem to apply.
This has a bunch of good stuff: http://www.whfreeman.com/college/pdfs/comappdfs/CoMap_c16.pdf Maple code for German banknotes http://home.att.net/~michael.engquist/Project4.mws Similar site http://modp.com/release/checkdigits/ -- Mike Stay metaweta@gmail.com http://math.ucr.edu/~mike