A026990 a(n) = Sum{(k+1)*T(n,k)}, 0<=k<=n, T given by A026681.

1, 3, 10, 30, 78, 189, 480, 1242, 3030, 7084, 17112, 42146, 99792, 229065, 540544, 1298851, 3025386, 6871084, 15993500, 37857267, 87275980, 196867143, 454118616, 1064055225, 2435780334, 5468505723, 12533827796, 29153115186