OFFSET
1,4
COMMENTS
Apply to A143667 the map : 0 -> 12, 1 -> 10, 2 -> 02. or apply to A003849 (the Fibonacci word), after grouping the terms 2 by 2, the map : "00" -> "12", "01"->"10, "10"->"02". Draws the Fibonacci word fractal curve when applying the following drawing rule: if "0" then draw a segment forward, if "1" then draw a segment forward and turn 90A degs right, if "2" the draw segment and turn 90A degs left.
REFERENCES
M. Lothaire, Combinatorics on words, Cambridge University Press.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
A. Monnerot-Dumaine, Fibonacci word fractal
MATHEMATICA
Partition[Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0}}]&, {0}, 10], 2] /. {{0, 0} -> {1, 2}, {0, 1} -> {1, 0}, {1, 0} -> {0, 2}} // Flatten (* Jean-François Alcover, Jul 16 2015 *)
PROG
(Haskell)
a143667 n = a143667_list !! (n-1)
a143667_list = f a003849_list where
f (0:0:ws) = 0 : f ws; f (0:1:ws) = 1 : f ws; f (1:0:ws) = 2 : f ws
-- Reinhard Zumkeller, Jul 29 2014
CROSSREFS
KEYWORD
nice,nonn
AUTHOR
Alexis Monnerot-Dumaine (alexis.monnerotdumaine(AT)gmail.com), Feb 10 2009
STATUS
approved