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%I #13 Jun 20 2022 21:33:55
%S 46,88,170,358,754,1690,3746,8722,19906,47458,110210,266818,626434,
%T 1532290,3623426,8925442,21208066,52491778,125134850,310731778,
%U 742387714,1847564290,4420706306,11018178562,26389889026,65840439298,157802201090
%N Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).
%H R. H. Hardin, <a href="/A234260/b234260.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) + 6*a(n-2) - 24*a(n-3) + 4*a(n-4) + 36*a(n-5) - 24*a(n-6).
%F Empirical g.f.: 2*x*(23 - 25*x - 185*x^2 + 212*x^3 + 294*x^4 - 324*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 6*x^2)). - _Colin Barker_, Oct 14 2018
%e Some solutions for n=5:
%e 2 2 2 2 0 2 2 1 2 1 1 1 2 2 2 2 1 2 1 1 1
%e 2 0 2 0 0 0 1 2 1 0 2 0 0 2 0 0 1 0 0 2 0
%e 1 1 1 2 0 2 1 0 1 1 1 1 1 1 1 1 0 1 0 0 0
%e 0 2 0 1 1 1 1 2 1 2 0 2 2 0 2 0 1 0 0 2 0
%e 1 1 1 0 2 0 1 0 1 1 1 1 1 1 1 1 0 1 0 0 0
%e 0 2 0 1 1 1 0 1 0 0 2 0 2 0 2 0 1 0 2 0 2
%Y Column 2 of A234266.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 22 2013
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