1/81 the number of (n+1) X 3 0..2 arrays with no 2 X 2 subblock being a reflection across the shared element pair of any horizontal or vertical neighbor.

A183813

1/81 the number of (n+1) X 3 0..2 arrays with no 2 X 2 subblock being a reflection across the shared element pair of any horizontal or vertical neighbor.

Terms

    a(0) =8a(1) =162a(2) =3256a(3) =65640a(4) =1321860a(5) =26630220a(6) =536415300a(7) =10805642100a(8) =217666494900

External references