%I #8 Mar 02 2018 10:00:15

%S 5,172,6548,250031,9548295,364637102,13925032958,531779578441,

%T 20307996787865,775536991678112,29616787512285048,1131028064429979731,

%U 43192546862380323515,1649469330720040937602,62991170251091380482818

%N Number of n X 4 0..3 arrays with values 0..3 introduced in row major order and no element equal to any horizontal or vertical neighbor.

%C Column 4 of A198715.

%H R. H. Hardin, <a href="/A198711/b198711.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 46*a(n-1) - 312*a(n-2) + 530*a(n-3) - 263*a(n-4).

%F Empirical g.f.: x*(5 - 58*x + 196*x^2 - 163*x^3) / ((1 - x)*(1 - 45*x + 267*x^2 - 263*x^3)). - _Colin Barker_, Mar 02 2018

%e Some solutions with all values from 0 to 3 for n=5:

%e ..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1

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

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

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

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

%Y Cf. A198715.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 29 2011