A136732 Column 2 of square array A136730.
1, 3, 9, 43, 324, 3510, 50528, 913377, 19918602, 509040779, 14918466255, 493115508126, 18143982947900, 735340631600946, 32542320101428755, 1561227609244084205, 80700623119099359600, 4470904603875492038790
Offset: 0