A140419 - OEIS

A140419

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

%I #4 Mar 31 2012 12:35:07

%S 1,5,8,21,175,1984,27783,566775,18973984,977497059,72692403175,

%T 7984795118976,1348773682858701,345874419612107295,

%U 131649476800621708800,74856171576736831201899

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

%K nonn

%O 2,2

%A _R. H. Hardin_, Jun 17 2008