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%I #7 Oct 24 2018 06:00:26
%S 81,340,1440,6064,25948,109200,466296,1962720,8385248,35292928,
%T 150759392,634547840,2710688576,11409244416,48737830912,205137173504,
%U 876305679104,3688361604096,15755932345856,66316572940288,283291082594304
%N Number of (n+1) X (1+1) 0..2 arrays with the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.
%H R. H. Hardin, <a href="/A238039/b238039.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 8*a(n-2) + 152*a(n-4) + 472*a(n-6) + 384*a(n-8).
%F Empirical g.f.: x*(81 + 340*x + 792*x^2 + 3344*x^3 + 2116*x^4 + 9008*x^5 + 1600*x^6 + 6912*x^7) / ((1 + 6*x^2)*(1 - 14*x^2 - 68*x^4 - 64*x^6)). - _Colin Barker_, Oct 24 2018
%e Some solutions for n=5:
%e ..2..1....2..1....1..0....1..1....2..2....2..1....0..2....0..2....1..1....2..2
%e ..2..2....0..0....1..0....2..0....2..2....0..0....2..2....2..0....0..2....2..0
%e ..1..0....2..0....2..1....1..0....1..1....0..0....1..1....1..2....0..1....1..0
%e ..1..1....1..0....0..2....1..2....0..2....1..2....1..0....1..0....2..1....0..0
%e ..2..2....1..2....0..2....0..2....1..2....0..1....2..0....2..2....2..1....2..1
%e ..2..1....2..1....1..2....2..0....1..1....0..1....2..2....2..0....1..1....2..2
%Y Column 1 of A238046.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 17 2014
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