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 A197229 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,3,0,1,2 for x=0,1,2,3,4. 5

%I

%S 1,7,12,31,79,186,465,1131,2776,6803,16663,40842,100065,245207,600844,

%T 1472287,3607663,8840098,21661545,53078827,130062864,318702387,

%U 780939327,1913591746,4689011265,11489821079,28154333788,68988586095,169047687279

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

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

%C Column 2 of A197235.

%H R. H. Hardin, <a href="/A197229/b197229.txt">Table of n, a(n) for n = 1..200</a>

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

%F Empirical g.f.: x*(1 + 6*x + 2*x^2 - 4*x^3 - x^4 - 2*x^5) / (1 - x - 3*x^2 - 2*x^3 + x^4 + x^5 + x^6). - _Colin Barker_, Feb 18 2018

%e Some solutions for n=4:

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

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 12 2011

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Last modified April 20 14:27 EDT 2019. Contains 322310 sequences. (Running on oeis4.)