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

%S 1,2,8,40,310,4155,89670,3070348,168002166,14759284768,2075629841521,

%T 467015770766284,168271584258210602,97113565640564063834,

%U 89738360022163805917690

%N Number of n X n symmetric binary matrices with every 1 adjacent horizontally (and vertically) to some other 1.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jun 15 2008