%I #11 Oct 24 2019 19:16:21
%S 1,2,4,7,15,24,50,81,165,266,544,875,1787,2876,5870,9445,19281,31022,
%T 63324,101887,207975,334624,683050,1099001,2243325,3609426,7367704,
%U 11854355,24197587,38932996,79471590,127866765,261006761
%N a(n) = Sum_{k=0..floor(n/2)} A027157(n-k, k).
%F Empirical g.f.: (1+x)^2*(1-x+x^2) / ((1-x)*(1-2*x^2-3*x^4-4*x^6)). - _Colin Barker_, Feb 20 2016
%K nonn
%O 0,2
%A _Clark Kimberling_