A234265 - OEIS

%I #11 Jun 20 2022 21:33:08

%S 3104,3746,4924,7304,11876,21164,39508,77060,152564,308756,627124,

%T 1294964,2673716,5617844,11778868,25220660,53769524,117585716,

%U 255267124,570940724,1262696756,2888073524,6501509428,15179569460,34712242484

%N Number of (n+1) X (7+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="/A234265/b234265.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*(1552 - 2783*x - 12469*x^2 + 22276*x^3 + 18954*x^4 - 33420*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   0 2 2 0 0 2 0 2     2 2 0 0 0 2 0 0     0 0 2 0 0 2 2 2

%e   0 0 2 2 0 0 0 0     2 0 0 2 0 0 0 2     2 0 0 0 2 2 0 2

%e   2 0 0 2 2 0 2 0     0 0 2 2 2 0 2 2     0 0 2 0 0 2 2 2

%e   2 2 0 0 2 2 2 2     2 0 0 2 0 0 0 2     2 0 0 0 2 2 0 2

%e   0 2 2 0 0 2 0 2     2 2 0 0 0 2 0 0     2 2 0 2 2 0 0 0

%e   2 2 0 0 2 2 2 2     0 2 2 0 2 2 2 0     2 0 0 0 2 2 0 2

%Y Column 7 of A234266.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 22 2013