Practical Numbers - Numberphile

Featuring Dr James Grime. More links & stuff in full description below ↓↓↓ Patreon: http://www.patreon.com/numberphile Practical Numbers (AKA panarithmic numbers) on the OEIS: https://oeis.org/A005153 James Grime: https://www.singingbanana.com His YouTube channel: https://www.youtube.com/user/singingbanana More James on Numberphile: http://bit.ly/grimevideos Numberphile is supported by the Simons Laufer Mathematical Sciences Institute (formerly 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 The Akamai Foundation - dedicated to encouraging the next generation of technology innovators and equitable access to STEM education - https://www.akamai.com/company/corporate-responsibility/akamai-foundation 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 Editing and animation by Pete McPartlan Numberphile T-Shirts and Merch: https://teespring.com/stores/numberphile 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 With thanks to Patrons, including: Juan Benet Jeff Straathof Ben Delo Ken Baron Andy B Michael Dunworth Yana Chernobilsky James Bissonette Jubal John Jeremy Buchanan Steve Crutchfield Ben White Andrei M Burke RAD Donato Matthew Schuster Ron Hochsprung Ubiquity Ventures John Zelinka Gnare Kannan Stanz Heather Liu Tracy Parry Ian George Walker Arnas Bernd Sing Valentin Alfred Wallace Alex Khein Doug Hoffman John Loach