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%I #7 Jan 18 2019 15:21:26
%S 24,102,594,3258,17346,90450,464250,2353338,11809746,58773858,
%T 290465706,1426996746,6974700162,33938314674,164494914138,
%U 794524032090,3825755303730,18370501130754,87990608484618,420498562000554
%N Number of n X 3 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.
%H R. H. Hardin, <a href="/A269047/b269047.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 10*a(n-1) - 29*a(n-2) + 20*a(n-3) - 4*a(n-4) for n>5.
%F Empirical g.f.: 6*x*(1 - x)*(1 - 2*x)*(4 - 11*x + 4*x^2) / (1 - 5*x + 2*x^2)^2. - _Colin Barker_, Jan 18 2019
%e Some solutions for n=4:
%e ..2..1..2. .1..2..0. .1..2..2. .1..2..2. .2..1..0. .0..0..0. .0..0..0
%e ..2..1..2. .1..0..1. .1..0..1. .1..2..2. .0..1..2. .0..1..0. .0..0..0
%e ..2..1..0. .0..0..0. .0..0..1. .1..2..1. .2..1..2. .0..1..2. .1..0..1
%e ..2..2..2. .0..0..0. .1..0..0. .0..0..1. .2..2..0. .2..1..2. .1..2..2
%Y Column 3 of A269052.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 18 2016
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