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%I #4 Feb 15 2016 15:02:12
%S 0,1344,12960,118584,1004184,8250912,66210264,522241560,4063962024,
%T 31282792704,238663638432,1807307152056,13599932970888,
%U 101786388133320,758232651966984,5625079743143376,41579318178922608,306353541215271960
%N Number of 4Xn 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.
%C Row 4 of A268904.
%H R. H. Hardin, <a href="/A268907/b268907.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 18*a(n-1) -111*a(n-2) +282*a(n-3) -333*a(n-4) +180*a(n-5) -36*a(n-6) for n>12
%e Some solutions for n=4
%e ..0..1..0..0. .0..0..0..1. .2..1..0..1. .1..0..0..0. .1..1..2..2
%e ..0..1..0..0. .0..0..0..1. .2..1..2..2. .1..0..1..0. .2..2..1..0
%e ..2..1..2..1. .0..0..0..1. .1..2..2..2. .0..0..1..2. .1..0..1..0
%e ..0..1..2..1. .1..0..2..2. .2..2..1..2. .0..0..2..2. .0..0..0..1
%Y Cf. A268904.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 15 2016
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