Half the number of n X n binary matrices, symmetric under 180 degree rotation, having equal row sums.
A140984
Half the number of n X n binary matrices, symmetric under 180 degree rotation, having equal row sums.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =35a(4) =226a(5) =7592a(6) =156752a(7) =22458249a(8) =1718157826a(9) =941605438142
External references
- oeis: A140984