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A221324 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.

%I A221324 #8 May 08 2014 18:42:09
%S A221324 17,866,46105,2460824,131347807,7010554450,374176705928,
%T A221324 19970973695923,1065911268786396,56890876705125765,
%U A221324 3036435876484206258,162063633563069131638,8649818983278197229631,461666606875092805859284
%N A221324 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.
%C A221324 Column 4 of A221328.
%H A221324 R. H. Hardin, <a href="/A221324/b221324.txt">Table of n, a(n) for n = 1..118</a>
%F A221324 Empirical: a(n) = 91*a(n-1) -2497*a(n-2) +29072*a(n-3) -168762*a(n-4) +513070*a(n-5) -765950*a(n-6) +359339*a(n-7) +283374*a(n-8) -252113*a(n-9) -12688*a(n-10) +38079*a(n-11) -6354*a(n-12) +289*a(n-13).
%e A221324 Some solutions for n=3:
%e A221324 ..1..1..2..1....0..1..0..1....0..2..1..2....0..2..2..2....2..1..1..0
%e A221324 ..0..0..1..2....1..2..2..2....0..0..2..0....1..0..1..2....2..0..1..1
%e A221324 ..1..0..2..1....2..0..0..1....2..0..1..2....1..0..1..0....1..2..1..0
%K A221324 nonn
%O A221324 1,1
%A A221324 _R. H. Hardin_, Jan 11 2013