Number of -1..1 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero.

A199825

Number of -1..1 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero.

Terms

    a(0) =2a(1) =4a(2) =4a(3) =10a(4) =22a(5) =34a(6) =66a(7) =138a(8) =250a(9) =472a(10) =944a(11) =1806a(12) =3450a(13) =6772a(14) =13172a(15) =25478a(16) =49794a(17) =97348a(18) =189772a(19) =371246a(20) =727506a(21) =1424586a(22) =2793034a(23) =5483342a(24) =10766950a(25) =21154424a(26) =41599648a(27) =81840866a(28) =161080918a(29) =317230034

External references