A027228 a(n) = Sum_{k=0..n} (k+1) * A026747(n, n-k).
1, 3, 10, 25, 73, 170, 468, 1050, 2799, 6138, 16043, 34644, 89390, 190913, 488285, 1034228, 2628861, 5532322, 14000177, 29311171, 73936801, 154145390, 387911301, 805899231, 2024537328, 4193625311, 10521409964, 21738996250
Offset: 0