A047005 T(n,n-3), array T given by A047000.
1, 2, 3, 14, 30, 143, 728, 3148, 13566, 56221, 231308, 939090, 3793530, 15237792, 61020524, 243678476, 971345694, 3866131073, 15371516800, 61064462784, 242432019936, 962016777729, 3816117832536, 15133756472226
Offset: 3