1/4 the number of n X 2 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

A186161

1/4 the number of n X 2 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Terms

    a(0) =1a(1) =7a(2) =48a(3) =321a(4) =2175a(5) =14748a(6) =99933a(7) =677283a(8) =4590168a(9) =31108893a(10) =210834267a(11) =1428886932a(12) =9683993481a(13) =65631317487a(14) =444803049600

External references