A234483 - OEIS

A234483

Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).

%I #11 Jun 20 2022 21:32:16

%S 62,242,944,3686,14402,56312,220334,862706,3380192,13252982,51996674,

%T 204137576,801957182,3152502002,12400248464,48805735046,192207885122,

%U 757400598872,2986264405454,11780750826866,46500068952512

%N Number of (n+1) X (1+1) 0..3 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="/A234483/b234483.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 7*a(n-1) - 9*a(n-2) - 12*a(n-3).

%F Empirical g.f.: 2*x*(31 - 96*x - 96*x^2) / ((1 - 4*x)*(1 - 3*x - 3*x^2)). - _Colin Barker_, Oct 15 2018

%e Some solutions for n=5:

%e 3 2 1 0 2 0 0 3 0 0 2 2 0 3 1 1 1 2 2 2

%e 3 0 0 1 0 0 0 1 3 1 2 0 1 2 3 1 1 0 3 1

%e 1 0 2 1 0 2 0 3 1 1 1 1 3 2 0 0 3 0 0 0

%e 0 1 1 2 3 3 2 3 0 2 0 2 3 0 1 3 1 0 0 2

%e 1 0 1 0 0 2 0 3 2 2 1 1 3 2 3 3 0 1 3 3

%e 2 3 1 2 1 1 2 3 1 3 0 2 2 3 3 1 3 2 3 1

%Y Column 1 of A234490.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 26 2013