"Excursions in Number Theory" by Ogilvy and Anderson (1966): "Until recent years the binary system was looked upon as something of a mathematical curio of only theoretical importance. Suddenly it has become indispensable, and would have had to be developed in a hurry had it not been ready to hand. This has been the story again and again throughout the history of mathematics: no part of mathematics is ever, in the long run, 'useless.' Most of number theory has very few 'practical' applications. That does not reduce its importance, and if anything it enhances its fascination. No one can predict when what seems to be a most obscure theorem may suddenly be called upon to play some vital and hitherto unsuspected role."
(Ten years later, Diffie-Hellman public key cryptography was published.) The Raku Study Group September 25, 2022 1pm in California, 9pm in the UK Zoom meeting link: https://us02web.zoom.us/j/84036607818?pwd=cW5pZ2x1dzFNaHFWQnNDcjZ3ZWFjQT09 Passcode: 4RakuRoll RSVPs are useful, though not needed: https://www.meetup.com/san-francisco-perl/events/288660627/