1/729 the number of (n+2) X 4 0..2 arrays with each 3 X 3 subblock trace equal to some horizontal or vertical neighbor 3 X 3 subblock trace.

A186955

1/729 the number of (n+2) X 4 0..2 arrays with each 3 X 3 subblock trace equal to some horizontal or vertical neighbor 3 X 3 subblock trace.

Terms

    a(0) =141a(1) =3783a(2) =112707a(3) =3277141a(4) =97400287a(5) =2888274935a(6) =85776954369

External references