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%I #10 Mar 14 2018 11:06:27
%S 3,19,137,1001,7305,53291,388741,2835697,20685009,150886255,
%T 1100633309,8028513089,58563541437,427188362291,3116100301045,
%U 22730208012457,165804141741249,1209448362939775,8822248421700605,64353360753783545
%N Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with no occupancy greater than 2.
%C Column 2 of A221303.
%H R. H. Hardin, <a href="/A221297/b221297.txt">Table of n, a(n) for n = 1..113</a>
%F Empirical: a(n) = 11*a(n-1) - 27*a(n-2) - a(n-3) + 8*a(n-4) - 16*a(n-5) - 6*a(n-6) + 2*a(n-7).
%F Empirical g.f.: x*(3 - 14*x + 9*x^2 + 10*x^3 - 12*x^4 - 4*x^5 + 2*x^6) / (1 - 11*x + 27*x^2 + x^3 - 8*x^4 + 16*x^5 + 6*x^6 - 2*x^7). - _Colin Barker_, Mar 14 2018
%e Some solutions for n=3:
%e ..1..1....0..1....1..0....1..2....2..0....2..0....2..1....1..1....1..2....2..2
%e ..0..1....2..0....2..2....2..0....2..0....2..0....1..0....2..0....0..2....0..0
%e ..2..1....2..1....0..1....1..0....0..2....2..0....0..2....1..1....1..0....1..1
%Y Cf. A221303.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 09 2013
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