Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

A318010

Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

Terms

    a(0) =2a(1) =8a(2) =28a(3) =97a(4) =338a(5) =1178a(6) =4105a(7) =14305a(8) =49850a(9) =173717a(10) =605368a(11) =2109583a(12) =7351463a(13) =25618337a(14) =89274637a(15) =311103754a(16) =1084132616a(17) =3777979256a(18) =13165480909a(19) =45878993986a(20) =159878860766a(21) =557144956745

External references