Number of n X n binary matrices, symmetric under horizontal and vertical reflection, with no more than 1 one in any 2 X 2 subblock.
A141483
Number of n X n binary matrices, symmetric under horizontal and vertical reflection, with no more than 1 one in any 2 X 2 subblock.
Terms
- a(0) =1a(1) =2a(2) =1a(3) =5a(4) =2a(5) =35a(6) =5a(7) =314a(8) =35a(9) =6427a(10) =314a(11) =202841a(12) =6427a(13) =12727570a(14) =202841a(15) =1355115601a(16) =12727570a(17) =269718819131a(18) =1355115601a(20) =269718819131
External references
- oeis: A141483