%I A006996 M0021
%S A006996 1,2,0,2,1,0,0,0,0,2,1,0,1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2,1,0,1,2,0,0,0,
%T A006996 0,1,2,0,2,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%U A006996 0,0,0,0,0,0,0,0,0,0,0,2,1,0,1,2,0,0,0,0,1,2,0,2,1,0,0,0,0,0,0,0,0,0,0
%N A006996 C(2n,n) mod 3.
%C A006996 Removing 0's from the sequence gives Thue-Morse sequence A001285 : 1,
               2,0,2,1,0,0,0,0,2,1,0,1,2,..->1,2,2,1,2,1,1,2,... - Benoit Cloitre 
               (benoit7848c(AT)orange.fr), Jan 04 2004
%C A006996 a(n) = 0 if n in A074940, a(n) = 1 if n in A074939, a(n) = 2 if n in 
               A074938.
%D A006996 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A006996 Michael Gilleland, <a href="selfsimilar.html">Some Self-Similar Integer 
               Sequences</a>
%F A006996 a(n)=A005704(n) mod 3. - Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 
               04 2004
%F A006996 A fixed point of the morphism : 1 -> 120, 2 -> 210, 0 -> 000 . - DELEHAM 
               Philippe (kolotoko(AT)wanadoo.fr), Jan 08 2004
%t A006996 Table[ Mod[ Binomial[2n, n], 3], {n, 0, 104}] (* Or *)
%t A006996 Nest[ Function[ l, {Flatten[(l /. {0 -> {0, 0, 0}, 1 -> {1, 2, 0}, 2 
               -> {2, 1, 0}})]}], {1}, 7] (from Robert G. Wilson v 28 2005)
%Y A006996 Sequence in context: A056615 A060989 A135298 this_sequence A112604 A072627 
               A069848
%Y A006996 Adjacent sequences: A006993 A006994 A006995 this_sequence A006997 A006998 
               A006999
%K A006996 nonn
%O A006996 0,2
%A A006996 N. J. A. Sloane (njas(AT)research.att.com), Jim Propp (propp(AT)math.wisc.edu)