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A220806 Equals one maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..2 n X 2 array. 2

%I

%S 2,8,38,168,726,3088,12974,54000,223118,916552,3747670,15266264,

%T 61997350,251143328,1015242974,4097067104,16510377630,66454603032,

%U 267215894086,1073591223944,4310358413046,17295539333552,69365195543182

%N Equals one maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..2 n X 2 array.

%C Column 2 of A220810.

%H R. H. Hardin, <a href="/A220806/b220806.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 7*a(n-1) - 11*a(n-2) - 3*a(n-3) - 4*a(n-4).

%F Empirical g.f.: 2*x*(1 - 3*x + 2*x^2 - 2*x^3) / ((1 - 4*x)*(1 - 3*x - x^2 - x^3)). - _Colin Barker_, Mar 13 2018

%e Some solutions for n=3:

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

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

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

%Y Cf. A220810.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 22 2012

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Last modified October 2 08:34 EDT 2022. Contains 357191 sequences. (Running on oeis4.)