A323183 - OEIS

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

(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