%I #4 Mar 31 2012 12:35:07
%S 1,4,32,512,14513,603485,29856303,1487335683,68719476736,2898212537994
%N Half the number of n X n symmetric binary matrices with adjacent rows differing in at most four positions.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jun 15 2008