A047128 T(n,n+3), array T as in A047120.
1, 4, 15, 56, 211, 798, 3030, 11550, 44193, 169652, 653158, 2521038, 9752516, 37802636, 146792136, 570924940, 2223730395, 8672669484, 33864089798, 132372227670, 517947357111, 2028479976186, 7950990968079, 31189593428478
Offset: 0