Number of n X n symmetric binary matrices with each 1 adjacent to exactly 2 horizontally, vertically or diagonally neighboring 1s.
A191344
Number of n X n symmetric binary matrices with each 1 adjacent to exactly 2 horizontally, vertically or diagonally neighboring 1s.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =11a(4) =47a(5) =294a(6) =2274a(7) =23217a(8) =346865a(9) =7054923a(10) =194307949a(11) =7369451741a(12) =380583130482
External references
- oeis: A191344