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%I #8 Feb 27 2019 11:45:40
%S 8,57,393,2719,18805,130063,899565,6221735,43031893,297624991,
%T 2058487997,14237288407,98470518885,681059680207,4710468607821,
%U 32579398179207,225331548533621,1558478965304063,10779035164411613,74551919956746807
%N Number of n X 3 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 0, 1 or 2 neighboring 1s.
%H R. H. Hardin, <a href="/A297369/b297369.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 7*a(n-1) - 4*a(n-3).
%F Empirical g.f.: x*(8 + x - 6*x^2) / (1 - 7*x + 4*x^3). - _Colin Barker_, Feb 27 2019
%e Some solutions for n=5:
%e ..1..1..1. .1..1..1. .0..0..1. .1..1..0. .1..0..0. .0..0..1. .1..1..0
%e ..0..0..0. .0..1..1. .0..0..1. .1..1..0. .1..0..0. .0..0..0. .0..1..0
%e ..1..1..1. .0..0..0. .1..1..0. .0..1..0. .0..0..0. .0..1..0. .0..0..0
%e ..0..1..1. .1..1..0. .0..0..1. .1..1..1. .1..0..1. .0..1..1. .1..0..0
%e ..0..0..1. .1..0..1. .0..0..0. .0..1..0. .0..0..1. .1..0..1. .1..0..0
%Y Column 3 of A297374.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 29 2017
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