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Number of nX6 binary arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.
1

%I #4 Feb 13 2016 07:36:51

%S 20,258,2607,23156,193573,1552272,12111209,92571436,696659613,

%T 5178525870,38112289517,278191828634,2016589831189,14532118028260,

%U 104191269908219,743719988895596,5288057396240333,37470071363668612,264689231027772351

%N Number of nX6 binary arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

%C Column 6 of A268766.

%H R. H. Hardin, <a href="/A268764/b268764.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +51*a(n-2) -214*a(n-3) -1074*a(n-4) +2018*a(n-5) +7713*a(n-6) -10572*a(n-7) -22926*a(n-8) +30116*a(n-9) +25283*a(n-10) -32400*a(n-11) -15148*a(n-12) +15184*a(n-13) +5660*a(n-14) -2688*a(n-15) -1024*a(n-16)

%e Some solutions for n=4

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

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

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

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

%Y Cf. A268766.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 13 2016