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A233970 Toothpick sequence on hexagonal net starting from the vertex of a 60-degree wedge (see Comments lines for precise definition). 5
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, 205, 213, 227, 249, 275, 291, 321, 353, 355, 359, 365, 375, 385, 395, 413, 437, 459, 469, 487, 515, 553, 581, 627, 683, 737, 745, 759, 781, 807 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Toothpicks are connected by their endpoints. The toothpicks placed in north direction are prohibited. The sequence gives the number of toothpicks after n-th stage in the structure. A233971 (the first differences) give the number of toothpicks added at n-th stage.

First differs from A169780 at a(24).

First differs from both A233764 and A233780 at a(25).

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, A161206, A161830, A169780, A182632, A182634, A182634, A182840, A233760, A233764, A233780, A233971, A233972.

Sequence in context: A283594 A233764 A233780 * A169780 A233760 A244780

Adjacent sequences:  A233967 A233968 A233969 * A233971 A233972 A233973

KEYWORD

nonn

AUTHOR

Omar E. Pol, Dec 18 2013

STATUS

approved

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Last modified September 23 19:38 EDT 2020. Contains 337315 sequences. (Running on oeis4.)