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A349041
a(n) is the Y-coordinate of the n-th point of the terdragon curve; sequence A349040 gives X-coordinates.
5
0, 0, 1, 1, 2, 1, 2, 2, 3, 3, 4, 3, 4, 3, 3, 2, 3, 2, 3, 3, 4, 4, 5, 4, 5, 5, 6, 6, 7, 6, 7, 6, 6, 5, 6, 5, 6, 5, 5, 4, 4, 5, 5, 4, 4, 3, 4, 3, 4, 3, 3, 2, 3, 2, 3, 3, 4, 4, 5, 4, 5, 5, 6, 6, 7, 6, 7, 6, 6, 5, 6, 5, 6, 6, 7, 7, 8, 7, 8, 8, 9, 9, 10, 9, 10, 9
OFFSET
0,5
COMMENTS
Coordinates are given on a hexagonal lattice with X-axis and Y-axis as follows (the Y-axis corresponds to the sixth primitive root of unity):
Y
/
/
0 ---- X
The terdragon curve can be represented using an L-system.
A265671, when interpreted as a sequence of directions, yields the same curve.
LINKS
EXAMPLE
The terdragon curve starts (on a hexagonal lattice) as follows:
+-----+
8\ 9
\
+-----+7
6\ /4\
\5/ \
+-----+
2\ 3
\
+-----+
0 1
- so a(0) = a(1) = 0,
a(2) = a(3) = a(5) = 1,
a(4) = a(6) = a(7) = 2,
a(8) = a(9) = 3.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
sign
AUTHOR
Rémy Sigrist, Nov 06 2021
STATUS
approved