The sequence 1 1 ∞ 5 6 3 3 3
For those who want to know more, this topic links nicely into A-D-E theory, Dynkin diagrams, and Coxeter groups.<p><a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;playlist?list=PL-XzhVrXIVeSVcV9iRJ4S9WAH1ryq4hTQ" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;playlist?list=PL-XzhVrXIVeSVcV9iRJ4S...</a><p><a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;playlist?list=PL-XzhVrXIVeQ298S6uCyoDGWNActWwnzZ" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;playlist?list=PL-XzhVrXIVeQ298S6uCyo...</a><p><a href="http:&#x2F;&#x2F;math.ucr.edu&#x2F;home&#x2F;baez&#x2F;week230.html" rel="nofollow">http:&#x2F;&#x2F;math.ucr.edu&#x2F;home&#x2F;baez&#x2F;week230.html</a><p><a href="https:&#x2F;&#x2F;unapologetic.wordpress.com&#x2F;category&#x2F;geometry&#x2F;root-systems&#x2F;" rel="nofollow">https:&#x2F;&#x2F;unapologetic.wordpress.com&#x2F;category&#x2F;geometry&#x2F;root-sy...</a><p><a href="http:&#x2F;&#x2F;www.math.harvard.edu&#x2F;~lurie&#x2F;papers&#x2F;thesis.pdf" rel="nofollow">http:&#x2F;&#x2F;www.math.harvard.edu&#x2F;~lurie&#x2F;papers&#x2F;thesis.pdf</a><p>Beautiful world this author is peeking into. Enjoy.