A027252 a(n) = Sum_{k=0..n} (k+1) * A026780(n, n-k).
1, 3, 10, 28, 80, 211, 569, 1455, 3806, 9564, 24565, 61080, 155041, 382920, 964163, 2370712, 5934974, 14548685, 36266755, 88711181, 220415107, 538305745, 1334040167, 3254193849, 8047710361, 19613210297, 48419611161
Offset: 0