Neil Sloane discusses peaceable queens and chess. Check out Brilliant (get 20% off their premium service): https://brilliant.org/numberphile (sponsor) More links & stuff in full description below ↓↓↓ Learn more at the OEIS entry (loads of links): https://oeis.org/A250000 References: Ainley, Stephen. Mathematical Puzzles. London: G Bell & Sons, 1977. Yukun Yao and Doron Zeilberger, Numerical and Symbolic Studies of the Peaceable Queens Problem, https://arxiv.org/abs/1902.05886 Other notable work by Michael De Vlieger, Benoit Jubin, Peter Karpov, Don Knuth, Rob Pratt, Bob Selcoe, Paul Tabatabai. More Numberphile videos with Neil Sloane: http://bit.ly/Sloane_Numberphile More chess-related videos: http://bit.ly/chess_numberphile 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