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A196850 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,1,0,2,4 for x=0,1,2,3,4.

%I A196850 #8 Mar 01 2018 11:00:36
%S A196850 2,11,38,136,496,1792,6440,23306,84180,303664,1096874,3960906,
%T A196850 14299036,51633110,186437376,673147554,2430568646,8776143806,
%U A196850 31687921122,114416191032,413124704992,1491673030176,5386005309890,19447328987316
%N A196850 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,1,0,2,4 for x=0,1,2,3,4.
%C A196850 Every 0 is next to 0 3's, every 1 is next to 1 1's, every 2 is next to 2 0's, every 3 is next to 3 2's, every 4 is next to 4 4's.
%C A196850 Column 2 of A196856.
%H A196850 R. H. Hardin, <a href="/A196850/b196850.txt">Table of n, a(n) for n = 1..200</a>
%F A196850 Empirical: a(n) = a(n-1) + 4*a(n-2) + 17*a(n-3) + 10*a(n-4) - 3*a(n-5) + 2*a(n-6) + 2*a(n-7) for n>8.
%F A196850 Empirical g.f.: x*(2 + 9*x + 19*x^2 + 20*x^3 + x^4 + 2*x^5 + x^6 - 6*x^7) / (1 - x - 4*x^2 - 17*x^3 - 10*x^4 + 3*x^5 - 2*x^6 - 2*x^7). - _Colin Barker_, Mar 01 2018
%e A196850 Some solutions for n=4:
%e A196850 ..0..0....1..1....1..1....2..0....1..1....1..1....2..0....0..0....2..0....0..0
%e A196850 ..1..0....0..0....0..0....0..0....0..2....0..2....0..1....0..0....0..0....2..0
%e A196850 ..1..0....2..0....0..1....0..0....2..0....0..0....0..1....2..1....0..1....2..0
%e A196850 ..0..0....1..1....0..1....1..1....1..1....0..2....0..0....0..1....0..1....0..2
%Y A196850 Cf. A196856.
%K A196850 nonn
%O A196850 1,1
%A A196850 _R. H. Hardin_, Oct 06 2011