A172309 Number of L-toothpicks added to the L-toothpick structure of A172308 (First quadrant) at the n-th stage.

0, 1, 2, 2, 2, 4, 4, 2, 4, 6, 6, 8, 6, 12, 10, 6, 4, 6, 10, 12, 10, 14, 14, 16, 16, 18, 14, 16, 12, 20, 22, 8, 8, 16, 18, 16, 10, 16, 20, 24, 26, 36, 24, 32, 30, 40, 28, 24

Offset

0,3

Links

Table of n, a(n) for n=0..47.

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

a(0) = 0, a(n) = A172305(n+1)/4, for n>=1.

Crossrefs

Cf. First differences of A172308.

Cf. A139250, A139251, A152978, A172304, A172305, A172306, A172307, A172308, A172310, A172311, A172312, A172313.

Sequence in context: A336299 A206424 A117728 * A130453 A259981 A070705

Adjacent sequences: A172306 A172307 A172308 * A172310 A172311 A172312

Keyword

more,nonn

Author

Omar E. Pol, Feb 06 2010

Extensions

More terms from Colin Barker, Apr 19 2015

Status

approved