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A280155 Number of n X 2 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

%I A280155 #9 Feb 13 2019 08:17:49
%S A280155 0,4,8,18,40,92,208,470,1060,2384,5352,11992,26824,59906,133592,
%T A280155 297510,661720,1470062,3262264,7231940,16016596,35439722,78349800,
%U A280155 173074816,382029988,842648168,1857362384,4091321478,9006604780,19815365450
%N A280155 Number of n X 2 0..1 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
%H A280155 R. H. Hardin, <a href="/A280155/b280155.txt">Table of n, a(n) for n = 1..210</a>
%F A280155 Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - 2*a(n-3) - 6*a(n-4) - 4*a(n-5) - a(n-6) for n>8.
%F A280155 Empirical g.f.: 2*x^2*(2 - 5*x^2 - 6*x^3 - x^4 + 2*x^5 + x^6) / (1 - x - 2*x^2 - x^3)^2. - _Colin Barker_, Feb 13 2019
%e A280155 Some solutions for n=4:
%e A280155 ..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..1
%e A280155 ..0..0. .0..0. .0..1. .0..0. .0..1. .1..0. .0..0. .0..1. .1..1. .0..0
%e A280155 ..1..1. .1..0. .1..1. .0..0. .0..0. .0..0. .0..0. .1..1. .1..0. .0..1
%e A280155 ..1..0. .0..0. .0..0. .0..1. .0..0. .0..0. .1..1. .1..0. .0..0. .1..1
%Y A280155 Column 2 of A280161.
%K A280155 nonn
%O A280155 1,2
%A A280155 _R. H. Hardin_, Dec 27 2016