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A172308 L-toothpick sequence in the first quadrant. 6
0, 1, 3, 5, 7, 11, 15, 17, 21, 27, 33, 41, 47, 59, 69, 75, 79 (list; graph; refs; listen; history; text; internal format)



The same as A172310 and A172304, but starting from half L-toothpick in the first quadrant.

Note that if n is odd then we add the small L-toothpicks to the structure, otherwise we add the large L-toothpicks to the structure.

We start at stage 0 with half L-toothpick: A segment from (0,0) to (1,1).

At stage 1 we place a small L-toothpick at the exposed toothpick end.

At stage 2 we place two large L-toothpicks.

At stage 3 we place two small L-toothpicks.

At stage 4 we place two large L-toothpicks.

And so on...

The sequence gives the number of L-toothpicks after n stages. A172309 (the first differences) gives the number of L-toothpicks added at the n-th stage.


Table of n, a(n) for n=0..16.

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS


Cf. A139250, A153000, A160120, A160170, A160172, A161206, A161328, A172304, A172305, A172306, A172307, A172309, A172310, A172311, A172312, A172313.

Sequence in context: A139252 A076245 A318953 * A190812 A238738 A059748

Adjacent sequences:  A172305 A172306 A172307 * A172309 A172310 A172311




Omar E. Pol, Feb 06 2010



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Last modified October 20 19:44 EDT 2018. Contains 316401 sequences. (Running on oeis4.)