%I #5 Mar 31 2012 12:37:30
%S 1380,49056,1732554,61289190,2167312950,76648760118,2710658447034,
%T 95862567834618,3390172069647198,119893318115163858,
%U 4240021127786852970,149948156963937950274,5302909535051211495570,187537150802706970729950
%N Half the number of (n+1)X4 0..2 arrays with every 2X2 subblock having exactly one duplicate clockwise edge difference
%C Column 3 of A209796
%H R. H. Hardin, <a href="/A209791/b209791.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 23*a(n-1) +474*a(n-2) -947*a(n-3) -13207*a(n-4) +27207*a(n-5) +14500*a(n-6) -33255*a(n-7) -1722*a(n-8) +5600*a(n-9) +816*a(n-10)
%e Some solutions for n=4
%e ..1..1..0..1....0..1..0..2....2..1..0..2....1..0..2..0....0..2..0..1
%e ..2..2..2..1....2..2..0..1....1..1..2..2....1..0..0..0....2..2..1..1
%e ..1..1..0..0....2..0..0..1....1..0..2..1....2..2..0..1....0..2..1..2
%e ..2..0..0..1....2..1..0..1....0..0..2..0....2..0..0..0....2..2..0..2
%e ..0..0..1..1....1..1..2..2....0..2..2..0....2..0..1..1....2..0..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 13 2012