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A198179 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,2,1,0,0 for x=0,1,2,3,4. 1

%I

%S 0,4,3,8,16,21,56,70,171,256,516,905,1622,3048,5293,9992,17564,32517,

%T 58330,106144,192767,348188,634426,1145535,2084360,3771658,6847617,

%U 12413706,22507930,40835531,74015802,134288434,243440863,441575714

%N Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,2,1,0,0 for x=0,1,2,3,4.

%C Every 0 is next to 0 0's, every 1 is next to 1 2's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 0's.

%C Column 2 of A198185.

%H R. H. Hardin, <a href="/A198179/b198179.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 3*a(n-2) +2*a(n-3) -2*a(n-4) -2*a(n-5) +4*a(n-7) -a(n-8) -3*a(n-9).

%F Empirical g.f.: x^2*(4 + 3*x - 4*x^2 - x^3 - x^4 + 6*x^5 - 3*x^6 - 7*x^7) / ((1 - x)*(1 + x - 2*x^2 - 4*x^3 - 2*x^4 - 4*x^7 - 3*x^8)). - _Colin Barker_, May 14 2018

%e All solutions for n=4:

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

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

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

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

%Y Cf. A198185.

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 21 2011

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Last modified May 13 23:41 EDT 2021. Contains 343868 sequences. (Running on oeis4.)