A189605 - OEIS

%I #5 Mar 31 2012 12:36:16

%S 1,13,72,464,2853,17617,108785,671452,4144996,25586605,157944449,

%T 974979853,6018479996,37151644524,229334423389,1415664871777,

%U 8738797243193,53943965676260,332992213004236,2055536935944305

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

%C Column 4 of A189610

%H R. H. Hardin, <a href="/A189605/b189605.txt">Table of n, a(n) for n = 1..200</a>

%F 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 Some solutions for 3X4

%e ..0..1..7..2....5..0..2..3....0..6..2..3....5..6..7..2....0..6..1..2

%e ..4..5..6..3....4..1.11..6....9..1..5..7....0..1.11..3....9..5.11..3

%e ..8..9.10.11....8..9.10..7....4..8.10.11....4..8..9.10....4..8.10..7

%K nonn

%O 1,2

%A _R. H. Hardin_ Apr 24 2011