Featuring James Grime. Bug Byte puzzle from Jane Street at https://bit.ly/janestreetbugbyte and programs at https://bit.ly/janestreetprograms (episode sponsor) More links & stuff in full description below ↓↓↓

Dr James Grime discussing triangular numbers, cubes, pentagonal numbers, hexagonal numbers, tetrahedral numbers and Pollock's Conjecture.

James Grime: https://www.singingbanana.com
More James on Numberphile: http://bit.ly/grimevideos

Sixty Symbols physics videos:    / sixtysymbols  

Patreon:   / numberphile  

Numberphile is supported by Jane Street. Learn more about them (and exciting career opportunities) at: https://bit.ly/numberphilejanestreet

We're also supported by the Simons Laufer Mathematical Sciences Institute (formerly MSRI): http://bit.ly/MSRINumberphile

Our thanks also to the Simons Foundation: https://www.simonsfoundation.org

NUMBERPHILE
Website: http://www.numberphile.com/
Numberphile on Facebook:   / numberphile  
Numberphile tweets:   / numberphile  
Subscribe: http://bit.ly/Numberphile_Sub

Video by Brady Haran and Pete McPartlan

Numberphile TShirts and Merch: https://teespring.com/stores/numberphile

Brady's videos subreddit:   / bradyharan  

Brady's latest videos across all channels: http://www.bradyharanblog.com/

Sign up for (occasional) emails: http://eepurl.com/YdjL9

Thanks to viewers for helping find the 343867 sums, including Arne, Alex, Sam, Felipe, Pablo, Ewoud and Michael.