Number of n X n symmetric binary matrices with every element adjacent horizontally (and vertically) to some 0.

A140419

Number of n X n symmetric binary matrices with every element adjacent horizontally (and vertically) to some 0.

Terms

    a(0) =1a(1) =5a(2) =8a(3) =21a(4) =175a(5) =1984a(6) =27783a(7) =566775a(8) =18973984a(9) =977497059a(10) =72692403175

External references