%I #3 Mar 31 2012 12:35:07
%S 1,3,27,171,3267,44235,1827981,53678097,4829415021,309226567689,
%T 60771492609849,8507664353592081,3659154831341169651,
%U 1121748956533219703391
%N Number of n X n integer matrices, symmetric about both diagonal and antidiagonal, with adjacent elements differing by no more than 1, counting matrices differing by a constant only once.
%K nonn
%O 1,2
%A _R. H. Hardin_, Aug 06 2008