One quarter the number of nX7 1..4 arrays with no two neighbors of any element equal to each other.

A183359

One quarter the number of nX7 1..4 arrays with no two neighbors of any element equal to each other.

Terms

    a(0) =972a(1) =36864a(2) =34992a(3) =63504a(4) =137088a(5) =331776a(6) =829440a(7) =1806336a(8) =3852288a(9) =8294400a(10) =18137088a(11) =40144896a(12) =88897536a(13) =196448256a(14) =433465344a(15) =955551744a(16) =2106667008a(17) =4645785600a(18) =10246588416a(19) =22600912896a(20) =49849804800a(21) =109947949056

External references