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.

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

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