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A323183 Consider the family of configurations E where E(0) consists of a single equilateral triangle, and for any k >= 0, E(k+1) is obtained by applying the Equithirds substitution to E(k). For k >= 5, the central node of E(k) has 6 equivalent tetravalent neighbors; let t(k) be the coordination sequence for one of those tetravalent nodes. This sequence is the limit of t(k) as k goes to infinity. 2
1, 4, 20, 39, 55, 71, 91, 107, 129, 147, 165, 181, 197, 217, 233, 253, 269, 289, 305, 325, 341, 361, 377, 399, 417, 435, 453, 471, 489, 507, 525, 543, 559, 575, 595, 611, 631, 647, 667, 683, 703, 719, 739, 755, 775, 791, 811, 827, 847, 863, 883, 899, 919, 935 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The variant relative to the central node appears to match A019557.

LINKS

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

Rémy Sigrist, Illustration of initial terms

Rémy Sigrist, C# program for A323183

Tilings Encyclopedia, Equithirds

Index entries for sequences related to coordination sequences

PROG

(C#) See Links section.

CROSSREFS

Cf. A019557, A323187 (partial sums).

Sequence in context: A119413 A044446 A232221 * A072977 A341895 A163365

Adjacent sequences: A323180 A323181 A323182 * A323184 A323185 A323186

KEYWORD

nonn

AUTHOR

Rémy Sigrist, Jan 06 2019

STATUS

approved

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Last modified February 3 18:25 EST 2023. Contains 360044 sequences. (Running on oeis4.)