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A189605 Number of nX4 array permutations with each element not moving, or moving one space E, S or NW.

%I A189605 #7 Jul 22 2025 11:50:00
%S A189605 1,13,72,464,2853,17617,108785,671452,4144996,25586605,157944449,
%T A189605 974979853,6018479996,37151644524,229334423389,1415664871777,
%U A189605 8738797243193,53943965676260,332992213004236,2055536935944305
%N A189605 Number of nX4 array permutations with each element not moving, or moving one space E, S or NW.
%C A189605 Column 4 of A189610
%H A189605 R. H. Hardin, <a href="/A189605/b189605.txt">Table of n, a(n) for n = 1..200</a>
%F A189605 Empirical: a(n) = 7*a(n-1) -3*a(n-2) -12*a(n-3) -11*a(n-4) +34*a(n-5) -27*a(n-6) +9*a(n-7) +7*a(n-8) +49*a(n-9) -82*a(n-10) +84*a(n-11) -54*a(n-12) +21*a(n-13) -6*a(n-14) +a(n-15)
%e A189605 Some solutions for 3X4
%e A189605 ..0..1..7..2....5..0..2..3....0..6..2..3....5..6..7..2....0..6..1..2
%e A189605 ..4..5..6..3....4..1.11..6....9..1..5..7....0..1.11..3....9..5.11..3
%e A189605 ..8..9.10.11....8..9.10..7....4..8.10.11....4..8..9.10....4..8.10..7
%K A189605 nonn
%O A189605 1,2
%A A189605 _R. H. Hardin_ Apr 24 2011