Half the number of n X n binary matrices, symmetric about both diagonal and antidiagonal, having equal row sums.
A140989
Half the number of n X n binary matrices, symmetric about both diagonal and antidiagonal, having equal row sums.
Terms
- a(0) =1a(1) =2a(2) =3a(3) =12a(4) =19a(5) =173a(6) =447a(7) =8068a(8) =36753a(9) =1320227a(10) =10915053a(11) =783176689a(12) =11979427593
External references
- oeis: A140989