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%I #8 Aug 11 2018 13:05:37
%S 3,31,258,2241,19408,167960,1453952,12585637,108943526,943035150,
%T 8163084148,70661144632,611655753520,5294603734144,45831055372945,
%U 396721972412987,3434097733826959,29726176177614458,257315201439500033
%N Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out straight through or left turns.
%C Row 2 of A221898.
%H R. H. Hardin, <a href="/A221899/b221899.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 5*a(n-1) + 26*a(n-2) + 45*a(n-3) + 34*a(n-4) - 2*a(n-5) - 4*a(n-6) + a(n-7).
%F Empirical g.f.: x*(3 + 16*x + 25*x^2 + 10*x^3 - 2*x^4 - 4*x^5 + x^6) / (1 - 5*x - 26*x^2 - 45*x^3 - 34*x^4 + 2*x^5 + 4*x^6 - x^7). - _Colin Barker_, Aug 11 2018
%e Some solutions for n=3:
%e ..0..2..3....0..0..0....0..3..0....2..0..2....1..1..2....0..4..1....1..2..1
%e ..1..0..0....3..2..1....2..0..1....2..0..0....0..2..0....0..1..0....0..1..1
%Y Cf. A221898.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 30 2013
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