Number of (n+1)X4 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.

A186476

Number of (n+1)X4 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.

Terms

    a(0) =1098a(1) =701a(2) =4686a(3) =4810a(4) =20224a(5) =21760a(6) =82632a(7) =101108a(8) =344804a(9) =465884a(10) =1445243a(11) =2112183a(12) =6085048a(13) =9483898a(14) =25738600a(15) =42272077a(16) =109291705a(17) =187344208a(18) =465619270a(19) =826593388a(20) =1989294067a(21) =3634249423a(22) =8519209648a(23) =15933856258a(24) =36556619512

External references