Number of 0..n arrays x(0..8) of 9 elements with zero 4th differences.

Terms

a(0) =2a(1) =3a(2) =4a(3) =5a(4) =6a(5) =9a(6) =12a(7) =17a(8) =22a(9) =37a(10) =52a(11) =71a(12) =94a(13) =117a(14) =148a(15) =197a(16) =250a(17) =305a(18) =364a(19) =453a(20) =546a(21) =655a(22) =768a(23) =897a(24) =1050a(25) =1227a(26) =1412a(27) =1623a(28) =1846a(29) =2121