%I
%S 0,1,0,0,1,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,0,1,0,0,1,1,0,0,1,1,0,1,1,
%T 0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,0,1,0,0,1,1,0,0,1,1,0,1,1,0,0,1,1,0,1,
%U 1,0,0,1,0,0,1,1,0,0,1,1,0,1,1,0,0,1,1,0,1,1,0,0,1,0,0,1,1,0,0,1,0,0,1,1,0
%N Fixed point of morphism 0>0100110, 1>0110110
%C Also a(n) is the least significant nonzero digit in the radix7 expansion of (n+1).
%C The sequence, interpreted as left/right turns by 120 degrees (each turn followed by a unit line in the current direction) defines a spacefilling curve (called R7dragon in the fxtbook, see link below).
%C Also sequence of zeros and ones by morphism F>F0F1F1F0F0F1F, 0>0, 1>1.
%H Joerg Arndt: <a href="http://www.jjj.de/fxt/#fxtbook">Matters Computational (The Fxtbook)</a> (section 1.31.5 "Dragon curves based on radixR counting", pp. 95101, image on p. 97).
%t Nest[Flatten[#/.{0>{0,1,0,0,1,1,0},1>{0,1,1,0,1,1,0}}]&,0,3] (* _Harvey P. Dale_, Mar 27 2015 *)
%K nonn
%O 0,1
%A _Joerg Arndt_, Apr 16 2010
