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Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..3 n X 2 array.
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%I #7 Jul 24 2018 09:39:56

%S 4,36,236,1528,9858,63592,410218,2646208,17069998,110114102,710317326,

%T 4582071648,29557748082,190669317026,1229957991200,7934137929012,

%U 51181052626992,330155610028966,2129747655406998,13738446168804038

%N Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..3 n X 2 array.

%C Column 2 of A218522.

%H R. H. Hardin, <a href="/A218516/b218516.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) + 3*a(n-2) - 4*a(n-4) + a(n-5).

%F Empirical g.f.: 2*x*(2 + 6*x + 4*x^2 + 2*x^3 - x^4) / (1 - 6*x - 3*x^2 + 4*x^4 - x^5). - _Colin Barker_, Jul 24 2018

%e Some solutions for n=3:

%e ..0..0....1..1....3..1....2..2....2..2....2..2....1..0....0..0....3..2....2..1

%e ..0..0....3..3....0..0....3..2....2..1....2..1....0..0....2..0....0..0....1..1

%e ..0..2....0..0....0..3....2..2....0..0....1..1....0..0....0..0....0..1....1..3

%Y Cf. A218522.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 31 2012