219022025

Appears in sequences

• Number of n X n binary arrays with all 1's connected only in a 3 X 3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.at n=9A146030
• Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.at n=20A146032
• Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.at n=21A146032