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%I
%S 4,441,33856,2572816,194881600,14755689729,1117092569476,
%T 84567501131481,6401965110822961,484642857129680209,
%U 36688499987102073289,2777397165745966328049,210254833741528740686404
%N Number of n X 4 arrays of occupancy after each element moves to some horizontal or vertical neighbor.
%C Column 4 of A217273.
%H R. H. Hardin, <a href="/A217269/b217269.txt">Table of n, a(n) for n = 1..38</a>
%F Empirical: a(n) = 102*a(n-1) -2037*a(n-2) +2098*a(n-3) +111987*a(n-4) -459828*a(n-5) -54016*a(n-6) +1828299*a(n-7) -2079066*a(n-8) +455875*a(n-9) +352710*a(n-10) -165978*a(n-11) +15218*a(n-12) +1308*a(n-13) -111*a(n-14) +a(n-15).
%e Some solutions for n=3
%e ..0..1..0..0....1..1..0..2....1..3..1..1....1..0..0..1....1..2..2..1
%e ..1..1..3..2....1..1..2..1....0..2..1..0....1..2..0..3....2..0..0..1
%e ..2..0..1..1....2..0..1..0....0..1..2..0....0..3..0..1....2..0..0..1
%Y Cf. A217273.
%K nonn
%O 1,1
%A _R. H. Hardin_ Sep 29 2012
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