Number of 2nX6 0..3 arrays with values 0..3 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.

A198599

Number of 2nX6 0..3 arrays with values 0..3 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.

Terms

    a(0) =2a(1) =32a(2) =674a(3) =14396a(4) =309770a(5) =6671450a(6) =143724590a(7) =3096625676a(8) =66720604082

External references