Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
%I
%S 4,6,7,8,9,11,12,13,14,16,17,20,22,23,25,26,29,31,32,34,37,38,40,41,
%T 43,46,47,48,51,53,55,58,59,60,61,62,64,65,68,69,80,81,84,86,87,89,90,
%U 93,95,101,102,105,106,117,119,125,127,128,130
%N Numbers in which the number of distinct base 4 digits is 2.
%K nonn,base
%O 1,1
%A _Clark Kimberling_