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

%I #4 Feb 15 2016 11:32:21

%S 20,475,9996,186732,3283890,55491832,911930096,14681855846,

%T 232688402028,3642322709900,56444213311842,867475989937560,

%U 13239446101273360,200865483664370358,3031934392327858732,45561723449682618252

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

%C Column 6 of A268886.

%H R. H. Hardin, <a href="/A268884/b268884.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 42*a(n-1) -665*a(n-2) +5138*a(n-3) -21972*a(n-4) +55274*a(n-5) -83769*a(n-6) +76202*a(n-7) -40273*a(n-8) +11304*a(n-9) -1296*a(n-10) for n>12

%e Some solutions for n=4

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

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

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

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

%Y Cf. A268886.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 15 2016