%I
%S 1,10,103,1031,10310,103103,1031031,10310310,103103103,1031031031,
%T 10310310310,103103103103,1031031031031,10310310310310,
%U 103103103103103,1031031031031031
%N Numbers written in base 4 whose digits are, in order, the first n terms of the periodic sequence with initial period 1,0,3.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10,0,1,10).
%F G.f.: x*(1+3*x^2) / ( (x1)*(10*x1)*(1+x+x^2) ).  _R. J. Mathar_, Apr 27 2015
%t With[{c=PadRight[{},21,{1,0,3}]},Table[FromDigits[Take[c,n]],{n,20}]] (* _Harvey P. Dale_, Dec 29 2011 *)
%K nonn,base,easy
%O 1,2
%A _Clark Kimberling_
