A139560 Number of new segments added to the toothpick structure drawing at the n-th step (extensions of earlier segments are not considered).

1, 2, 2, 2, 4, 4, 2, 2, 4, 4, 4, 8, 12, 8, 2, 2, 4, 4, 4, 8, 12, 8, 4, 8, 12, 12, 16, 28, 32, 16, 2, 2, 4, 4, 4, 8, 12, 8, 4, 8, 12, 12, 16, 28, 32, 16, 4, 8, 12, 12, 16, 28, 32, 20, 16, 28, 36, 40, 60, 88, 80, 32

Offset: 1

Author

Omar E. Pol, May 17 2008

Keywords

• nonn

Comments

First differences of A139252.

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, A139251, A139252, A139253, A139254, A139559.

Formula

a(n)=A139252(n)-A139252(n-1).

Extensions

Terms after a(28) from Nathaniel Johnston, Mar 29 2011