1/4 the number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.

A209545

1/4 the number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.

Terms

    a(0) =7a(1) =105a(2) =5075a(3) =723636a(4) =294738262a(5) =345350598642

External references