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%I #7 Oct 20 2018 03:58:26
%S 17152,18712,21928,28744,43912,80392,177928,471304,1451272,4984072,
%T 18341128,70221064,274644232,1086143752,4319755528,17229430024,
%U 68818582792,275076103432,1099908005128,4398839250184,17593771506952
%N Number of (n+1) X (6+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.
%H R. H. Hardin, <a href="/A235891/b235891.txt">Table of n, a(n) for n = 1..147</a>
%F Empirical: a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3).
%F Conjectures from _Colin Barker_, Oct 20 2018: (Start)
%F G.f.: 8*x*(2144 - 12669*x + 16384*x^2) / ((1 - x)*(1 - 2*x)*(1 - 4*x)).
%F a(n) = 4*(3906 + 189*2^n + 4^n).
%F (End)
%e Some solutions for n=4:
%e ..3..3..3..3..2..0..3....2..3..3..3..0..2..1....0..2..2..2..0..2..0
%e ..3..3..3..3..2..0..3....2..3..3..3..0..2..1....0..2..2..2..0..2..0
%e ..3..3..3..3..2..0..3....2..3..3..3..0..2..1....2..0..0..0..2..0..2
%e ..3..3..3..3..2..0..3....2..3..3..3..0..2..1....2..0..0..0..2..0..2
%e ..3..3..3..3..2..0..3....2..3..3..3..0..2..1....0..2..2..2..0..2..0
%Y Column 6 of A235893.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 16 2014
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