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%I A279971 #7 Feb 12 2019 12:02:23
%S A279971 1,3,9,31,108,366,1205,3873,12207,37859,115842,350412,1049545,3116655,
%T A279971 9185349,26890375,78253896,226510362,652483133,1871302893,5345409483,
%U A279971 15213423371,43153001406,122024489304,344061371665,967537410459
%N A279971 Number of n X 2 0..1 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
%H A279971 R. H. Hardin, <a href="/A279971/b279971.txt">Table of n, a(n) for n = 1..210</a>
%F A279971 Empirical: a(n) = 9*a(n-1) - 30*a(n-2) + 45*a(n-3) - 30*a(n-4) + 9*a(n-5) -a(n-6).
%F A279971 Empirical g.f.: x*(1 - 2*x)*(1 - 4*x + 4*x^2 + 3*x^3) / (1 - 3*x + x^2)^3. - _Colin Barker_, Feb 12 2019
%e A279971 Some solutions for n=4:
%e A279971 ..0..0. .0..1. .0..1. .0..1. .0..1. .0..1. .0..0. .0..0. .0..0. .0..0
%e A279971 ..1..1. .0..0. .1..0. .1..1. .0..1. .1..0. .1..0. .1..0. .1..1. .1..0
%e A279971 ..1..0. .0..1. .0..0. .1..0. .0..1. .1..0. .1..0. .1..1. .0..0. .1..1
%e A279971 ..0..1. .0..0. .0..1. .0..1. .1..1. .0..0. .1..1. .1..0. .0..1. .0..0
%Y A279971 Column 2 of A279977.
%K A279971 nonn
%O A279971 1,2
%A A279971 _R. H. Hardin_, Dec 24 2016

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