Number of 0..7 arrays x(0..n+1) of n+2 elements with zero n-1st differences.

Terms

a(0) =1a(1) =8a(2) =16a(3) =36a(4) =64a(5) =112a(6) =118a(7) =228a(8) =236a(9) =574a(10) =958a(11) =2110a(12) =1434a(13) =4316a(14) =2560a(15) =8448a(16) =18834a(17) =60888a(18) =38672a(19) =73250a(20) =15518a(21) =42050a(22) =48352a(23) =309524