%I A086905
%S A086905 1,0,2,1,5,5,15,20,50,76,176,286,638,1078,2354,4081,8789,15521,33099,
%T A086905 59279,125477,227239,478193,873885,1830271,3370029,7030571,13027729,
%U A086905 27088871,50469889,104647631,195892564,405187826,761615284,1571990936
%N A086905 Sum_{k=0..n} (-1)^(n-k)*binomial(k,floor(k/2)).
%C A086905 Kn{\"o}del walks starting and ending at 0, with n steps.
%H A086905 H. Prodinger, <a href="http://www.mat.univie.ac.at/~slc/opapers/s50proding.html">
               The Kernel Method: a collection of examples</a>
%F A086905 G.f.: (sqrt((1+2*x)/(1-2*x))-1)/2/x/(1+x).
%Y A086905 Cf. A036256, A001405.
%Y A086905 First column of triangle A101491.
%Y A086905 Sequence in context: A119245 A128731 A129157 this_sequence A167638 A054651 
               A145324
%Y A086905 Adjacent sequences: A086902 A086903 A086904 this_sequence A086906 A086907 
               A086908
%K A086905 nonn
%O A086905 0,3
%A A086905 Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 19 2003