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%I #8 Oct 06 2018 06:15:10
%S 24,56,252,1048,4458,18850,79810,337850,1430144,6054098,25627862,
%T 108487018,459242866,1944049234,8229473620,34836688334,147469316688,
%U 624261386538,2642599067830,11186547787492,47354459831826
%N Number of n X 4 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally.
%H R. H. Hardin, <a href="/A232937/b232937.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 10*a(n-2) + 15*a(n-3) + 4*a(n-4) - 6*a(n-5) - a(n-6) + 3*a(n-7) - a(n-8) for n>9.
%F Empirical g.f.: 2*x*(12 + 16*x - 22*x^2 - 62*x^3 - 23*x^4 + 26*x^5 + 6*x^6 - 13*x^7 + 4*x^8) / (1 - x - 10*x^2 - 15*x^3 - 4*x^4 + 6*x^5 + x^6 - 3*x^7 + x^8). - _Colin Barker_, Oct 06 2018
%e Some solutions for n=5:
%e ..0..1..0..0....2..2..2..2....2..1..2..1....2..2..2..2....1..0..0..0
%e ..0..0..0..0....2..2..2..2....2..2..2..2....1..2..2..2....0..0..0..0
%e ..1..0..1..0....1..2..2..2....2..2..2..1....2..2..2..1....0..0..1..0
%e ..0..0..0..0....2..2..2..2....2..2..2..2....2..1..2..2....0..0..0..0
%e ..1..0..0..1....2..2..2..2....1..2..1..2....2..2..1..2....0..1..0..0
%Y Column 4 of A232941.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 02 2013
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