|
%I #11 Nov 28 2014 22:09:18
%S 2,1,1,2,2,1,2,1,1,2,1,1,2,2,1,2,2,1,1,2,1,2,2,1,2,1,1,2,2,1,2,2,1,2,
%T 1,1,2,1,1,2,2,1,2,1,1,2,1,2,2,1,2,2,1,1,2,1,1,2,2,1,2,1,1,2,1,1,2,2,
%U 1,2,2,1,2,1,1,2,1,2,2,1,1,2,1,1,2,2,1,2,1,1,2,1,1,2,2,1,2,2,1,1,2,1,2,2,1
%N a(n)=3-k(n), where k=A000002=Kolakoski sequence; also the sequence of runlengths of a is k.
%C The anti-Kolakoski sequence: a(n) never equals the length of the n-th run. Start with a(1)=2, then the first run is of length 1 and a(2)=1; thus the 2nd run is of length 2 and a(3)=1, thus a(4)=a(5)=2, etc. - _Jean-Christophe Hervé_, Nov 10 2014
%t a2 = {1, 2, 2}; Do[ a2 = Join[a2, {1 + Mod[n-1, 2]}], {n, 3, 70}, {i, 1, a2[[n]]}]; 3 - a2 (* _Jean-François Alcover_, Jun 18 2013 *)
%Y Cf. A088569 (essentially the same sequence).
%K nonn
%O 1,1
%A _Clark Kimberling_
|
