Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X3 plus 2,1 2,2 2,3 1,2 3,2.
A146004
Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X3 plus 2,1 2,2 2,3 1,2 3,2.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =1a(4) =4a(5) =7a(6) =21a(7) =46a(8) =195a(9) =635a(10) =3736a(11) =16722a(12) =140702a(13) =874897a(14) =10218521a(15) =89150959a(16) =1456627028a(17) =17686096248a(18) =403908679949
External references
- oeis: A146004