Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X2 zee 1,1 1,2 1,3 2,3 2,4 in any orientation.
A146131
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X2 zee 1,1 1,2 1,3 2,3 2,4 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =5a(7) =9a(8) =21a(9) =39a(10) =159a(11) =427a(12) =2501a(13) =9027a(14) =58503a(15) =271185a(16) =2371669a(17) =14600987a(18) =167228191a(19) =1344019107a(20) =19775648697a(21) =206847230557
External references
- oeis: A146131