A221933 - OEIS

%I #9 Aug 11 2018 13:10:11

%S 6,105,1599,24535,376389,5773962,88575493,1358791848,20844539836,

%T 319765562424,4905362062396,75250682972713,1154382737872290,

%U 17708802802243865,271661803663808763,4167426584055854255

%N Number of n X 3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.

%C Column 3 of A221937.

%H R. H. Hardin, <a href="/A221933/b221933.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 14*a(n-1) + 21*a(n-2) - 5*a(n-3) - 26*a(n-4) + a(n-5).

%F Empirical g.f.: x*(6 + 21*x + 3*x^2 - 26*x^3 + x^4) / (1 - 14*x - 21*x^2 + 5*x^3 + 26*x^4 - x^5). - _Colin Barker_, Aug 11 2018

%e Some solutions for n=3:

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

%e ..0..1..0....0..2..0....1..0..1....2..1..0....2..0..0....0..3..0....0..4..0

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

%Y Cf. A221937.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 01 2013