Half the number of nX3 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

A185829

Half the number of nX3 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Terms

    a(0) =1a(1) =10a(2) =30a(3) =118a(4) =393a(5) =1430a(6) =5004a(7) =17877a(8) =63181a(9) =224324a(10) =794939a(11) =2819380a(12) =9995857a(13) =35445025a(14) =125677385a(15) =445630567a(16) =1580102608a(17) =5602722348a(18) =19866041906a(19) =70440800557a(20) =249768066156a(21) =885624613914

External references