Number of (n+1)X9 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.

A186481

Number of (n+1)X9 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.

Terms

    a(0) =27101a(1) =35081a(2) =101108a(3) =286290a(4) =479785a(5) =1286113a(6) =1894849a(7) =5977657a(8) =8078233a(9) =25049545a(10) =34600393a(11) =103930809a(12) =154520201a(13) =437740901a(14) =693356465a(15) =1854858401a(16) =3085313121a(17) =7883094433a(18) =13654582357a(19) =33612555865a(20) =60183013369a(21) =143706271561

External references