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%I #10 Jan 19 2019 08:44:39
%S 16,148,1164,8532,59916,408596,2727564,17914580,116170764,745617300,
%T 4745165964,29984668756,188330955276,1176750424852,7319499656844,
%U 45347466532308,279961285570572,1722988944076436,10574188575966348
%N Number of n X 2 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once.
%H R. H. Hardin, <a href="/A269137/b269137.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 12*a(n-1) - 38*a(n-2) + 12*a(n-3) - a(n-4) for n>5.
%F Empirical g.f.: 4*x*(4 - 11*x - x^2 - x^3 + x^4) / (1 - 6*x + x^2)^2. - _Colin Barker_, Jan 19 2019
%e Some solutions for n=4:
%e ..2..0. .3..3. .1..0. .2..2. .3..0. .2..1. .0..0. .0..1. .3..3. .0..1
%e ..2..2. .1..1. .1..1. .2..3. .1..0. .0..1. .0..1. .0..0. .1..1. .0..3
%e ..3..1. .1..3. .3..1. .0..1. .0..1. .1..1. .1..1. .1..2. .1..1. .1..1
%e ..1..1. .3..3. .0..0. .0..1. .0..0. .3..1. .0..2. .0..2. .3..0. .1..0
%Y Column 2 of A269143.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 20 2016
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