Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either three adjacent vertically or three adjacent horizontally.
A145761
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either three adjacent vertically or three adjacent horizontally.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =6a(7) =9a(8) =29a(9) =71a(10) =252a(11) =692a(12) =3368a(13) =13077a(14) =79134a(15) =377418a(16) =2968590a(17) =18765157a(18) =189063004a(19) =1516592933a(20) =19680440925a(21) =204860397699
External references
- oeis: A145761