Number of 0..n arrays x(0..8) of 9 elements with zero 6th differences.

Terms

a(0) =2a(1) =5a(2) =8a(3) =21a(4) =34a(5) =53a(6) =118a(7) =267a(8) =516a(9) =901a(10) =1454a(11) =2249a(12) =3264a(13) =5135a(14) =7616a(15) =11061a(16) =15434a(17) =21089a(18) =28008a(19) =36687a(20) =49294a(21) =65037a(22) =84056a(23) =107327a(24) =134670a(25) =167275a(26) =204986a(27) =256111a(28) =315260a(29) =385087