%I #9 Oct 26 2019 16:16:44
%S 1,3,10,28,80,211,569,1455,3806,9564,24565,61080,155041,382920,964163,
%T 2370712,5934974,14548685,36266755,88711181,220415107,538305745,
%U 1334040167,3254193849,8047710361,19613210297,48419611161
%N a(n) = Sum_{k=0..n} (k+1) * A026780(n, n-k).
%K nonn
%O 0,2
%A _Clark Kimberling_