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 A221405 Number of nX4 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two 1

%I

%S 4,44,436,4518,47156,492102,5133044,53529806,558164472,5819704716,

%T 60677191216,632619159318,6595610902832,68764677891112,

%U 716926331557236,7474513869766556,77927543824707370,812454058048811426

%N Number of nX4 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two

%C Column 4 of A221408

%H R. H. Hardin, <a href="/A221405/b221405.txt">Table of n, a(n) for n = 1..94</a>

%F Empirical: a(n) = 19*a(n-1) -110*a(n-2) +250*a(n-3) -446*a(n-4) +939*a(n-5) -1112*a(n-6) -343*a(n-7) -822*a(n-8) +692*a(n-9) +1957*a(n-10) +2810*a(n-11) -1975*a(n-12) -59*a(n-13) -2679*a(n-14) +738*a(n-15) +1088*a(n-16) +1258*a(n-17) -418*a(n-18) -562*a(n-19) +192*a(n-20) +336*a(n-21) +32*a(n-22) -32*a(n-23)

%e Some solutions for n=3

%e ..0..2..2..0....0..2..0..2....2..2..0..2....2..2..0..2....0..2..0..0

%e ..2..2..0..0....0..2..0..2....0..0..0..2....0..2..0..0....2..0..0..2

%e ..0..0..2..2....2..0..0..2....2..2..0..0....2..0..2..0....2..2..2..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 15 2013

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Last modified June 20 10:00 EDT 2021. Contains 345162 sequences. (Running on oeis4.)