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A233780 Number of toothpicks and D-toothpicks after n-th stage in a D-toothpick "wide" triangle (see Comments lines for definition). 6
0, 1, 3, 5, 9, 11, 15, 21, 29, 31, 35, 41, 51, 61, 69, 83, 99, 101, 105, 111, 121, 131, 141, 159, 183, 201, 209, 223, 245, 271, 287, 317, 349, 351, 355, 361, 371, 381, 391, 409, 433, 451, 461, 479, 509, 547, 573, 615, 667, 701, 709, 723, 745, 771 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The D-toothpicks placed in northwest or northeast direction both are prohibited, except in the substructures in which the symmetry could be broken, so a(44) = 509, not 507. For another version with broken symmetry in some substructures see A233764. See also A231348, a simpler cellular automaton based in triangles which has essentially a similar structure.

A233781 (the first differences) gives the number of toothpicks or D-toothpicks added at n-th stage.

First differs from A169780 at a(24).

First differs from A233970 at a(25).

First differs from A233764 at a(44).

LINKS

Table of n, a(n) for n=0..53.

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

Index entries for sequences related to toothpick sequences

CROSSREFS

Cf. A139250, A169780, A220500, A231348, A233764, A233781, A233970.

Sequence in context: A261141 A283594 A233764 * A233970 A169780 A233760

Adjacent sequences:  A233777 A233778 A233779 * A233781 A233782 A233783

KEYWORD

nonn

AUTHOR

Omar E. Pol, Dec 15 2013

STATUS

approved

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Last modified April 25 21:06 EDT 2019. Contains 322461 sequences. (Running on oeis4.)