A139252 Number of segments needed to draw the toothpick structure of A139250 as it is after n stages.

0, 1, 3, 5, 7, 11, 15, 17, 19, 23, 27, 31, 39, 51, 59, 61, 63, 67, 71, 75, 83, 95, 103, 107, 115, 127, 139, 155, 183, 215, 231, 233, 235, 239, 243, 247, 255, 267, 275, 279, 287, 299, 311, 327, 355, 387, 403, 407, 415

Offset: 0

Author

Omar E. Pol, May 17 2008

Keywords

• nonn

Comments

Contribution from Omar E. Pol, Sep 16 2012 (Start):

It appears that A147614(n)/a(n) converge to 4.

It appears that A139250(n)/a(n) converge to 3.

It appears that A160124(n)/a(n) converge to 2.

(End)

Examples

			For n = 3, after three stages the toothpick structure of A139250 contains seven toothpicks (A139250(3) = 7), however the toothpick structure can be essentially represented by five segments, so a(3) = 5. - _Omar E. Pol_, Sep 16 2012
		

Links

• Nathaniel Johnston, Table of n, a(n) for n = 0..256
• 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.]
• Nathaniel Johnston, C script for computing table of terms
• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Crossrefs

Cf. A139250, A139251, A139253, A147614, A160124, A139254, A139255, A160128.

Extensions

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