%I #7 Oct 20 2018 11:02:16
%S 292,1068,3516,11656,38700,128920,429252,1429352,4757532,15839544,
%T 52732564,175561496,584466876,1945813896,6477977380,21566507704,
%U 71798959308,239032817336,795786352324,2649328064136,8820125707548
%N Number of (n+1) X (2+1) 0..2 arrays colored with the difference of the maximum and minimum in each 2 X 2 subblock.
%H R. H. Hardin, <a href="/A236049/b236049.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 4*a(n-2) + 5*a(n-3) + 21*a(n-4) + 12*a(n-5) + 4*a(n-6) for n>9.
%F Empirical g.f.: 4*x*(73 + 194*x + 320*x^2 + 602*x^3 + 377*x^4 + 21*x^5 - 142*x^6 - 80*x^7 - 16*x^8) / (1 - x - 4*x^2 - 5*x^3 - 21*x^4 - 12*x^5 - 4*x^6). - _Colin Barker_, Oct 20 2018
%e Some solutions for n=4:
%e ..0..0..2....2..2..1....2..2..0....1..2..2....1..0..2....2..1..1....1..1..2
%e ..1..1..1....0..1..2....2..1..1....1..2..2....1..1..1....1..0..0....1..0..1
%e ..1..1..2....1..0..0....1..0..1....0..1..2....1..1..0....0..0..0....2..1..1
%e ..0..0..1....2..1..0....0..1..2....0..0..1....1..2..1....2..1..1....1..1..1
%e ..2..1..1....1..2..2....2..2..2....2..0..1....0..1..1....1..1..1....2..0..1
%Y Column 2 of A236055.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 18 2014