A047145 T(n,n-3), array T as in A047140.
1, 5, 19, 68, 250, 935, 3473, 12850, 48066, 181540, 686960, 2600830, 9893064, 37819055, 144917337, 556011134, 2138565128, 8248348136, 31873293528, 123320614254, 477883163716, 1855021589250, 7210702449848, 28058894828756
Offset: 3