%I A088917
%S A088917 1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,
%T A088917 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,
%U A088917 0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%N A088917 Central Delannoy numbers (mod 3).
%C A088917 Also Apery numbers (mod 3). More generally also sum(k=0,n,binomial(n,
               k)^x*binomial(n+k,k)^y) (mod 3) for any x>=1 in N and any odd y>=1.
%H A088917 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               CantorFractal.html">Cantor Fractal</a>
%F A088917 a(A005823(n))=1; a(A081606(n))=0
%F A088917 a(n)=A001850(n)-3*floor(A001850(n)/3)
%o A088917 (PARI) a(n)=sum(k=0,n,binomial(n,k)*binomial(n+k,k))%3
%Y A088917 Cf. A005823, A005258, A081606, A001850.
%Y A088917 Sequence in context: A102242 A005369 A108340 this_sequence A014933 A011643 
               A015941
%Y A088917 Adjacent sequences: A088914 A088915 A088916 this_sequence A088918 A088919 
               A088920
%K A088917 nonn
%O A088917 0,1
%A A088917 Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 30 2003