%I A081868
%S A081868 1,2,3,10,11,28,29,36,37,38,39,82,83,90,91,92,93,108,109,110,111,118,
%T A081868 119,244,245,252,253,254,255,270,271,272,273,280,281,324,325,326,327,
%U A081868 334,335,352,353,360,361,362,363
%N A081868 Numbers n such that sum(k=1,n,C(2k,k) mod 3) is even.
%Y A081868 Sequence in context: A032804 A047473 A008509 this_sequence A092986 A006092 
               A015859
%Y A081868 Adjacent sequences: A081865 A081866 A081867 this_sequence A081869 A081870 
               A081871
%K A081868 nonn
%O A081868 1,2
%A A081868 Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 12 2003