A160724 a(n) = A160714(n)*3.

0, 3, 6, 15, 18, 27, 36, 63, 66, 75, 84, 111, 120, 147, 174, 255, 336, 339

Offset: 0

Author

Omar E. Pol, Jun 02 2009

Keywords

• nonn
• more

Comments

The sequence gives the number of T-toothpicks in the structure after n rounds.

See A160172 and A160714 for more information about T-toothpick sequences.

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

Crossrefs

Cf. A139250, A160172, A160173, A160714, A160726.

Extensions

a(9)-a(17) from 3*A160714(n) by Jinyuan Wang, Mar 14 2020