%I #17 Jan 02 2019 23:13:53
%S 1,2,1,3,1,2,1,4,1,2,1,3,1,2,1,1,2,1,3,1,2,1,4,1,2,1,3,1,2,1,2,1,3,1,
%T 2,1,4,1,2,1,3,1,2,1,1,2,1,3,1,2,1,4,1,2,1,3,1,2,1,3,1,2,1,4,1,2,1,3,
%U 1,2,1,1,2,1,3,1,2,1,4,1,2,1,3,1,2,1,2,1,3,1,2,1,4,1,2
%N Fixed point of the morphism 1 -> 12, 2 -> 13, 3 -> 14, 4 -> 1, starting from a(1) = 1.
%H Robert Israel, <a href="/A317954/b317954.txt">Table of n, a(n) for n = 1..10000</a>
%p A:= [1]:
%p for n from 1 while nops(A) < 1000 do
%p A:= subs([1=(1,2),2=(1,3),3=(1,4),4=1],A)
%p od:
%p A; # _Robert Israel_, Aug 21 2018
%t Nest[Flatten[#/.{0 -> {0, 1}, 1 -> {1, 2}, 2 -> {2, 0}}] &, {0}, 7] (* _G. C. Greubel_, Jan 02 2019 *)
%Y Cf. A003849, A092782, A100619, A317955.
%K nonn
%O 1,2
%A _N. J. A. Sloane_ and _Doron Zeilberger_, Aug 21 2018