A047093 T(n,n-2), array T as in A047089.
1, 3, 8, 19, 98, 335, 1381, 5164, 20306, 77915, 303445, 1175121, 4574312, 17794125, 69379714, 270671995, 1057440462, 4134573755, 16182570293, 63389522371, 248511714532, 974976349772, 3827778946917, 15037653341387
Offset: 2