%I #7 Oct 12 2018 15:00:12

%S 673,12593,231713,4279065,79003521,1458813409,26937444801,

%T 497411686793,9184935953377,169604155276817,3131820756402657,

%U 57830550281200505,1067868451774107585,19718695887361293761,364115043587212161409

%N Number of (n+1) X (3+1) 0..2 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1.

%H R. H. Hardin, <a href="/A234117/b234117.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 20*a(n-1) - 10*a(n-2) - 324*a(n-3) - 277*a(n-4) + 144*a(n-5).

%F Empirical g.f.: x*(673 - 867*x - 13417*x^2 - 11213*x^3 + 5904*x^4) / (1 - 20*x + 10*x^2 + 324*x^3 + 277*x^4 - 144*x^5). - _Colin Barker_, Oct 12 2018

%e Some solutions for n=2:

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

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

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

%Y Column 3 of A234122.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 19 2013