Number of n X n symmetric binary matrices with each 1 adjacent to no more than 1 diagonally or antidiagonally neighboring 1.

A191551

Number of n X n symmetric binary matrices with each 1 adjacent to no more than 1 diagonally or antidiagonally neighboring 1.

Terms

    a(0) =2a(1) =8a(2) =33a(3) =297a(4) =4032a(5) =91392a(6) =3461143a(7) =214272233a(8) =22066261672

External references