Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 2X3 U in any orientation.

A146058

Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 2X3 U in any orientation.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =3a(7) =7a(8) =13a(9) =21a(10) =51a(11) =159a(12) =577a(13) =2001a(14) =7625a(15) =31703a(16) =159573a(17) =881761a(18) =5519227a(19) =36692597a(20) =286423433a(21) =2406566921a(22) =23662937019a(23) =247567053249

External references