%I #7 Oct 26 2018 11:18:32

%S 4,20,92,418,1898,8588,38888,175974,796550,3604984,16316908,73849786,

%T 334252546,1512838756,6847231728,30990953678,140267248638,

%U 634858320528,2873411390324,13005245181090,58862597882746,266415951317884

%N Number of 2 X n 0..3 arrays with no element equal to zero plus the sum of elements to its left or two plus the sum of the elements above it, modulo 4.

%H R. H. Hardin, <a href="/A239650/b239650.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) + 12*a(n-2) - 18*a(n-3) - 29*a(n-4) + 19*a(n-5) + 38*a(n-6) + 8*a(n-7).

%F Empirical g.f.: 2*x*(2 + 4*x - 8*x^2 - 13*x^3 + 8*x^4 + 19*x^5 + 4*x^6) / (1 - 3*x - 12*x^2 + 18*x^3 + 29*x^4 - 19*x^5 - 38*x^6 - 8*x^7). - _Colin Barker_, Oct 26 2018

%e Some solutions for n=5:

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

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

%Y Row 2 of A239649.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 23 2014