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%I #6 Jun 20 2022 19:30:10
%S 220,546,1240,3384,8416,24420,64240,194124,527920,1640076,4548400,
%T 14411004,40441936,130023180,367611280,1195404444,3396165040,
%U 11145399276,31767426160,105049443324,300084387856,998758590540,2857390403920
%N Number of (n+1) X (2+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant-stress 1 X 1 tilings).
%H R. H. Hardin, <a href="/A234558/b234558.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) +30*a(n-2) -132*a(n-3) -331*a(n-4) +1720*a(n-5) +1530*a(n-6) -11280*a(n-7) -1324*a(n-8) +39136*a(n-9) -12360*a(n-10) -67968*a(n-11) +39456*a(n-12) +46080*a(n-13) -34560*a(n-14)
%e Some solutions for n=5:
%e 4 0 4 2 2 2 4 4 4 3 1 3 0 0 0 0 4 0 0 0 0
%e 2 2 2 0 4 0 0 4 0 2 4 2 4 0 4 4 4 4 0 4 0
%e 4 0 4 1 1 1 4 4 4 4 2 4 4 4 4 0 4 0 4 4 4
%e 1 1 1 4 0 4 4 0 4 0 2 0 4 0 4 1 1 1 4 0 4
%e 0 4 0 2 2 2 3 3 3 3 1 3 4 4 4 0 4 0 3 3 3
%e 3 3 3 0 4 0 0 4 0 2 4 2 4 0 4 4 4 4 0 4 0
%Y Column 2 of A234564.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 28 2013
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