%I #9 Feb 22 2019 06:03:06
%S 5,19,72,270,1027,3879,14691,55589,210418,796360,3014159,11408021,
%T 43177713,163420621,618521718,2341006856,8860343731,33535006265,
%U 126924727467,480390130557,1818201106700,6881605261574,26045793772285
%N Number of n X 3 0..1 arrays with each 1 horizontally or vertically adjacent to 0 or 2 1s.
%H R. H. Hardin, <a href="/A295046/b295046.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 3*a(n-3) - 2*a(n-4) - 6*a(n-5) + 3*a(n-6) - a(n-7) + a(n-9).
%F Empirical g.f.: x*(5 + 4*x - 5*x^2 - 7*x^3 - 4*x^4 + 2*x^5 - x^6 + x^7 + x^8) / (1 - 3*x - 4*x^2 + 3*x^3 + 2*x^4 + 6*x^5 - 3*x^6 + x^7 - x^9). - _Colin Barker_, Feb 22 2019
%e Some solutions for n=7:
%e ..0..0..0. .0..1..1. .0..0..0. .1..0..1. .0..0..0. .0..0..1. .0..0..0
%e ..1..0..0. .0..1..1. .0..0..1. .0..0..0. .0..0..0. .0..0..0. .1..0..1
%e ..0..0..0. .1..0..0. .0..0..0. .1..0..0. .0..1..1. .1..0..1. .0..0..0
%e ..1..0..0. .0..1..0. .0..1..0. .0..1..0. .0..1..1. .0..0..0. .1..0..0
%e ..0..0..1. .1..0..0. .0..0..1. .1..0..0. .0..0..0. .0..0..1. .0..1..1
%e ..0..0..0. .0..0..1. .1..0..0. .0..1..0. .1..0..1. .0..0..0. .0..1..1
%e ..1..0..1. .0..0..0. .0..0..1. .1..0..1. .0..0..0. .0..0..1. .0..0..0
%Y Column 3 of A295051.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 13 2017
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