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%I #8 May 02 2018 09:23:03
%S 1,4,13,45,160,565,2005,7108,25209,89401,317056,1124425,3987721,
%T 14142276,50154949,177872293,630816160,2237161405,7933993245,
%U 28137553540,99788579953,353895752689,1255075518976,4451069407761,15785519335825
%N Number of n X 2 array permutations with each element moving one space diagonally, horizontally or vertically.
%C Column 2 of A189355.
%H R. H. Hardin, <a href="/A189348/b189348.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 3*a(n-1) +3*a(n-2) -3*a(n-3) -3*a(n-4) +a(n-5).
%F Empirical g.f.: x*(1 + x - 2*x^2 - 3*x^3 + x^4) / ((1 - x)*(1 - 2*x - 5*x^2 - 2*x^3 + x^4)). - _Colin Barker_, May 02 2018
%e Some solutions for 3 X 2:
%e ..1..3....2..0....3..0....1..0....1..0....3..0....1..0....1..3....1..3....1..0
%e ..0..5....3..1....5..1....4..5....3..5....4..1....4..2....5..0....0..2....3..2
%e ..2..4....5..4....2..4....2..3....2..4....5..2....5..3....2..4....5..4....5..4
%Y Cf. A189355.
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 20 2011
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