%I #8 Jul 30 2019 18:19:17
%S 1,1,3,3,3,12,21,30,66,138,264,525,1029,2460,5079,10344,22197,50421,
%T 108966,229827,498432,1136190,2495118,5390319,11879355,27012990,
%U 60008826,131877372,292070991,670433502,1500384540,3327218859,7449719727,17089051899
%N a(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=a(2)=1 and a(3)=3.
%K nonn
%O 1,3
%A _Clark Kimberling_
%E Offset corrected and title improved by _Sean A. Irvine_, Jul 30 2019