Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a one by five or five by one block.

A145968

Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a one by five or five by one block.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =3a(8) =5a(9) =7a(10) =16a(11) =27a(12) =69a(13) =151a(14) =481a(15) =1224a(16) =4362a(17) =12863a(18) =54770a(19) =198381a(20) =1006602a(21) =4307827a(22) =25870297a(23) =130523404a(24) =917353447a(25) =5499437681a(26) =46147817424a(27) =329292463469

External references