A176405 - OEIS

%I #10 Mar 27 2015 11:58:45

%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 radix-7 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 space-filling curve (called R7-dragon 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 radix-R counting", pp. 95-101, 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