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A230470 Number of 2 X n 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero. 1

%I

%S 0,0,0,36,216,1260,6912,38340,213192,1188252,6624720,36934452,

%T 205906968,1147892364,6399246240,35674383780,198876914280,

%U 1108695761532,6180739391088,34456287198996,192086358160824,1070839950246252

%N Number of 2 X n 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.

%H R. H. Hardin, <a href="/A230470/b230470.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - a(n-2) - 12*a(n-3) + 20*a(n-4) + 24*a(n-5).

%F Empirical g.f.: 36*x^3 / ((1 + x)*(1 - 7*x + 8*x^2 + 4*x^3 - 24*x^4)). - _Colin Barker_, Sep 21 2018

%e Some solutions for n=4:

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

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

%Y Row 2 of A230469.

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 20 2013

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Last modified August 10 19:57 EDT 2022. Contains 356039 sequences. (Running on oeis4.)