1/729 the number of (n+2)X(n+2) 0..2 arrays with each 3X3 subblock trace equal to some horizontal or vertical neighbor 3X3 subblock trace.

A186953

1/729 the number of (n+2)X(n+2) 0..2 arrays with each 3X3 subblock trace equal to some horizontal or vertical neighbor 3X3 subblock trace.

Terms

    a(0) =0a(1) =3783a(2) =5903759a(3) =47796308777

External references