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://www.youtube.com/playlist?list=PL-XzhVrXIVeSVcV9iRJ4S9WAH1ryq4hTQ" rel="nofollow">https://www.youtube.com/playlist?list=PL-XzhVrXIVeSVcV9iRJ4S...</a><p><a href="https://www.youtube.com/playlist?list=PL-XzhVrXIVeQ298S6uCyoDGWNActWwnzZ" rel="nofollow">https://www.youtube.com/playlist?list=PL-XzhVrXIVeQ298S6uCyo...</a><p><a href="http://math.ucr.edu/home/baez/week230.html" rel="nofollow">http://math.ucr.edu/home/baez/week230.html</a><p><a href="https://unapologetic.wordpress.com/category/geometry/root-systems/" rel="nofollow">https://unapologetic.wordpress.com/category/geometry/root-sy...</a><p><a href="http://www.math.harvard.edu/~lurie/papers/thesis.pdf" rel="nofollow">http://www.math.harvard.edu/~lurie/papers/thesis.pdf</a><p>Beautiful world this author is peeking into. Enjoy.