Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

A301842

Number of 2Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

Terms

    a(0) =2a(1) =8a(2) =25a(3) =81a(4) =263a(5) =855a(6) =2778a(7) =9027a(8) =29333a(9) =95316a(10) =309725a(11) =1006437a(12) =3270370a(13) =10626915a(14) =34531665a(15) =112209036a(16) =364618033a(17) =1184809305a(18) =3849982618a(19) =12510339087a(20) =40651763813a(21) =132096011916a(22) =429239834325

External references