%I #6 Mar 31 2012 12:37:29
%S 7,105,5075,723636,294738262,345350598642,1159953545419801,
%T 11179084602659460822,309007688117388883362757,
%U 24500703075201459753727015849,5572033834554753242178727061445290
%N 1/4 the number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences
%C Diagonal of A209553
%H R. H. Hardin, <a href="/A209545/b209545.txt">Table of n, a(n) for n = 1..13</a>
%e Some solutions for n=4
%e ..0..2..0..2..0....2..3..0..1..2....2..3..0..1..2....3..0..3..0..3
%e ..2..0..2..0..2....3..2..1..2..1....3..2..1..0..1....0..3..0..3..0
%e ..0..2..0..2..0....2..1..0..1..2....2..1..2..3..2....1..2..1..2..1
%e ..2..0..2..0..2....1..2..1..0..1....3..0..1..2..3....2..3..0..3..2
%e ..0..2..0..2..0....0..1..0..1..0....0..3..2..1..0....3..2..1..2..3
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 10 2012