Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either two adjacent vertically or two adjacent horizontally.
A145777
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either two adjacent vertically or two adjacent horizontally.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =20a(7) =66a(8) =223a(9) =972a(10) =5286a(11) =31417a(12) =228724a(13) =2000916a(14) =20634823a(15) =248726975a(16) =3651917796a(17) =62467383723
External references
- oeis: A145777