A161836 Number of concave-convex hexagons in the Y-toothpick structure of A160120 after n rounds.
0, 0, 0, 0, 3, 3, 3, 3, 9, 15
Offset: 0
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.]
- N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS