1/6 the number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock containing all three values.

A183595

1/6 the number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock containing all three values.

Terms

    a(0) =6a(1) =204a(2) =17174a(3) =3831324a(4) =2220901926

External references