This has been discussed before, but it may meet your needs. See: http://astro.umsystem.edu/atm/ARCHIVES/NOV96/msg00524.html and http://www.rtmcastronomyexpo.org/archives/photos/94RTMC06.jpg For more information, search the archives http://astro.umsystem.edu/atm/ for Mersenne _______________________________________________ ATM mailing list http://www.atmlist.net/