OFFSET
1,3
COMMENTS
a(n) is the number of toothpicks added at the n-th round in the toothpick structure of A168112.
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
FORMULA
Observation: It appears that a(2^i+2) = 3, for i>0.
a(n) = A160731(n)/2. [From Nathaniel Johnston, Mar 28 2011]
EXAMPLE
If written as a triangle, begins:
1;
1;
2;
3,3;
3,6,7,6;
3,6,7,8,9,16,17,10;
3,6,7,8,9,16,17,12,9,16,19,22,31,46,41,18;
Rows converge to A168114.
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Dec 07 2009
EXTENSIONS
Terms after a(34) from Nathaniel Johnston, Mar 28 2011
STATUS
approved