login
Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops or left turns
1

%I #5 Jan 30 2013 19:12:11

%S 0,8,0,90,204,1297,4608,23159,92312,425249,1799292,7982268,34469356,

%T 151243634,657198136,2872557590,12512098304,54609983231,238067509008,

%U 1038559461306,4528789386340,19753331212394,86145964341528

%N Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops or left turns

%C Column 3 of A221890

%H R. H. Hardin, <a href="/A221887/b221887.txt">Table of n, a(n) for n = 1..48</a>

%F Empirical: a(n) = 14*a(n-2) +28*a(n-3) +a(n-4) -104*a(n-5) -92*a(n-6) +84*a(n-7) +19*a(n-8) -4*a(n-9) +75*a(n-10) -15*a(n-12) -8*a(n-13) +4*a(n-14)

%e Some solutions for n=4

%e ..1..1..0....0..1..0....0..1..0....0..2..1....1..2..0....0..3..1....1..1..1

%e ..0..3..1....1..3..1....1..3..1....1..2..0....0..2..1....1..1..0....0..3..0

%e ..0..3..0....0..1..1....0..2..1....0..1..1....0..1..1....0..2..0....0..3..0

%e ..1..1..1....1..3..0....1..2..0....1..3..0....1..3..0....1..2..1....1..1..1

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 30 2013