A233780 Number of toothpicks and D-toothpicks after n-th stage in a D-toothpick "wide" triangle (see Comments lines for definition).

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

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: A283594 A339173 A233764 * A233970 A169780 A233760

Adjacent sequences: A233777 A233778 A233779 * A233781 A233782 A233783

Keyword

nonn

Author

Omar E. Pol, Dec 15 2013

Status

approved