Half the number of (n+1)X7 0..2 arrays with every 2X2 subblock having two or four distinct clockwise edge differences.
A209509
Half the number of (n+1)X7 0..2 arrays with every 2X2 subblock having two or four distinct clockwise edge differences.
Terms
- a(0) =2187a(1) =53247a(2) =1323270a(3) =33137271a(4) =832374135a(5) =20934997854a(6) =526815563193
External references
- oeis: A209509