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Number of nX7 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.
1

%I #4 Feb 15 2016 14:57:46

%S 576,34344,1585800,66210264,2611960344,99308573208,3679171151832,

%T 133712637011640,4788143315276472,169455769674019992,

%U 5940079034652505944,206577531186380751096,7136252899974195705720,245118805391945325271896

%N Number of nX7 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

%C Column 7 of A268904.

%H R. H. Hardin, <a href="/A268903/b268903.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 84*a(n-1) -2466*a(n-2) +31428*a(n-3) -206469*a(n-4) +750384*a(n-5) -1513404*a(n-6) +1574640*a(n-7) -656100*a(n-8)

%e Some solutions for n=2

%e ..0..1..0..0..0..0..1. .1..0..1..0..0..0..1. .0..0..0..1..2..2..1

%e ..2..2..1..0..1..2..1. .1..0..0..0..0..2..2. .1..1..2..2..1..2..2

%Y Cf. A268904.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 15 2016