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%I #8 Oct 11 2018 10:11:18
%S 48,184,648,2440,8712,32456,116872,432456,1565704,5768392,20957064,
%T 76995656,280355592,1028180936,3749152392,13733970760,50125386248,
%U 183485530824,670067844488,2451649137224,8956514967816,32760264743368
%N Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 6.
%H R. H. Hardin, <a href="/A233675/b233675.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 12*a(n-2) - 4*a(n-3) - 16*a(n-4).
%F Empirical g.f.: 8*x*(6 + 17*x - 14*x^2 - 28*x^3) / (1 - x - 12*x^2 + 4*x^3 + 16*x^4). - _Colin Barker_, Oct 11 2018
%e Some solutions for n=5:
%e ..3..1....1..2....2..2....0..1....1..1....3..2....2..1....1..2....3..1....1..1
%e ..2..2....1..0....1..3....0..2....2..0....1..2....3..1....1..3....2..1....2..3
%e ..0..1....1..2....1..2....0..1....2..1....1..0....2..2....2..2....3..1....1..1
%e ..2..1....0..0....0..2....0..2....0..1....2..2....3..1....0..1....3..2....2..3
%e ..0..1....1..2....0..1....1..2....2..1....0..1....2..2....2..2....3..1....2..1
%e ..2..2....1..3....2..1....0..0....3..3....2..2....1..0....1..0....2..2....3..1
%Y Column 1 of A233682.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 14 2013
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