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A161836
Number of concave-convex hexagons in the Y-toothpick structure of A160120 after n rounds.
5
0, 0, 0, 0, 3, 3, 3, 3, 9, 15
OFFSET
0,5
LINKS
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]
KEYWORD
more,nonn
AUTHOR
Omar E. Pol, Jun 21 2009
STATUS
approved