%I #4 Mar 31 2012 12:35:07
%S 3,13,160,2817,119145,8890880,1270451663,347961207321,183722336587008,
%T 185316870246113925,357804006282379850529,1323503980097432239521792,
%U 9379216327375443934023725295,127291943357342220975708211213101
%N Number of n X n symmetric binary matrices with every element adjacent to some zero horizontally or vertically.
%K nonn
%O 2,1
%A _R. H. Hardin_, Jun 18 2008