Number of nX3 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

A301946

Number of nX3 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.

Terms

    a(0) =1a(1) =5a(2) =20a(3) =83a(4) =342a(5) =1411a(6) =5820a(7) =24007a(8) =99026a(9) =408471a(10) =1684896a(11) =6950003a(12) =28667966a(13) =118252075a(14) =487776260a(15) =2012021183a(16) =8299356842a(17) =34233896031a(18) =141210898600a(19) =582478776747

External references