Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in two by two blocks.

A145859

Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in two by two blocks.

Terms

    a(0) =1a(1) =2a(2) =1a(3) =2a(4) =2a(5) =7a(6) =5a(7) =38a(8) =12a(9) =182a(10) =72a(11) =1536a(12) =513a(13) =21327a(14) =4531a(15) =360939a(16) =68662a(17) =9098657a(18) =1429824a(19) =345351393a(20) =40840428a(21) =18058986880a(22) =1747979822a(24) =106711196102

External references