%I #5 Apr 15 2013 11:57:04
%S 4,1,2,3,4,1,1,2,1,2,3,1,2,3,4,1,1,1,2,1,1,2,1,2,3,1,1,2,1,2,3,1,2,3,
%T 4,1,1,1,1,2,1,1,1,2,1,1,2,1,2,3,1,1,1,2,1,1,2,1,2,3,1,1,2,1,2,3,1,2,
%U 3,4,1,1,1,1,1,2,1,1,1,1,2,1,1,1,2,1,1,2,1,2,3,1,1,1,1,2,1,1,1,2,1,1,2,1,2
%N Fixed point of: 4-->1234, 3->123, 2-->12, 1->1
%t Flatten[NestList[#/.(Thread[#->Range[#]]&[Range[4]])&,{4},8]] (* _Peter J. C. Moses_, Apr 15 2013 *)
%o (PARI) v=[4];for(n=1,200,for(i=1,v[n],v=concat(v,i));v);a(n)=v[n];
%Y Cf. A073645
%K nonn
%O 1,1
%A _Benoit Cloitre_, Feb 18 2009