Featuring Neil Sloane from the Online Encyclopedia of Integer Sequences (OEIS). Lunar Arithmetic (aka Dismal Arithmetic) More links & stuff in full description below ↓↓↓ Neil Sloane is the founder of the OEIS: https://oeis.org/ Lunar Primes: https://oeis.org/A087097 Lunar Squares: https://oeis.org/A087019 The original paper on lunar arithmetic (formerly dismal arithmetic) by David Applegate, Marc LeBrun, and Neil Sloane: https://cs.uwaterloo.ca/journals/JIS/VOL14/Sloane/carry2.pdf Sloane's Gap: https://www.youtube.com/watch?v=_YysNM2JoFo Six Sequences: https://www.youtube.com/watch?v=VDD6FDhKCYA Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. https://www.simonsfoundation.org/outreach/science-sandbox/ And support from Math For America - https://www.mathforamerica.org/ NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: http://www.patreon.com/numberphile Numberphile T-Shirts: null Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/ Brady's latest videos across all channels: http://www.bradyharanblog.com/ Sign up for (occasional) emails: http://eepurl.com/YdjL9 ---------------- As expected many people ask "what is the point of this"... And fair enough. Rather than answering everyone individually, here is my view (I am just the film-maker, not a mathematician) - Brady ↓↓↓ 1. Because it is fun and creative - and playing with new ideas is good for your brain. 2. Because you never know what "bending the rules" will teach you - what techniques, insights and breakthroughs will occur that may have more useful applications... Just look at much of John Conway's work... So much playfulness and so many games - yet many ideas and insightful mathematics has fallen out of that. Lunar arithmetic is never going to be used to build a bridge or design an iPhone (I certainly hope not!!!)... But neither is it just throwing ALL rules out of the window... It is creating a new arbitrary set of rules and seeing what happens... What IS a prime number in this new landscape? What pattern do the squares follow? And what light might that shed on more conventional mathematics? Also... If you are not buying that and think it's just nonsensical playing... I say the following... It may be true that this will not cure cancer or help people live longer - but what is the point of living longer if we can't play, imagine, and do fun stuff like this? And if you think this is just child's play - read the paper: https://cs.uwaterloo.ca/journals/JIS/VOL14/Sloane/carry2.pdf