|
%I #12 Jun 13 2018 11:23:42
%S 270,780,2016,5952,17976,54432,165936,504912,1538496,4687392,14278656,
%T 43507872,132544416,403832352,1230343776,3748436832,11420384736,
%U 34794057312,106006675296,322968189792,983980623456,2997875890272
%N Number of (n+1) X 3 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly two counterclockwise and two clockwise edge increases.
%C Column 2 of A206094.
%H R. H. Hardin, <a href="/A206088/b206088.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 6*a(n-2) + 4*a(n-3) - 10*a(n-4) for n>6.
%F Empirical g.f.: 6*x*(45 + 85*x - 64*x^2 - 304*x^3 - 82*x^4 + 80*x^5) / ((1 - x)*(1 - 6*x^2 - 10*x^3)). - _Colin Barker_, Jun 13 2018
%e Some solutions for n=4:
%e ..2..1..2....2..1..2....2..0..2....2..1..0....0..1..0....1..0..1....2..1..0
%e ..2..2..0....2..2..0....1..2..2....2..2..1....0..2..0....0..0..1....2..1..1
%e ..1..2..2....1..2..2....2..2..0....1..2..2....0..1..0....0..2..0....0..2..1
%e ..2..0..2....0..1..1....0..0..1....2..1..1....0..2..0....1..0..0....0..0..2
%e ..2..2..1....0..1..2....1..0..0....1..1..2....0..1..1....0..0..1....1..0..2
%Y Cf. A206094.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 03 2012
| 