|
%I #12 Jun 12 2018 11:12:29
%S 66,216,714,2430,8274,28242,96402,329130,1123698,3836538,13098738,
%T 44721882,152690034,521316378,1779885426,6076908954,20747864946,
%U 70837641882,241854837618,825744066714,2819266591602,9625578232986
%N Number of (n+1) X 3 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.
%C Column 2 of A205823.
%H R. H. Hardin, <a href="/A205817/b205817.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - a(n-2) - 4*a(n-3) + 2*a(n-4).
%F Empirical g.f.: 6*x*(11 - 8*x - 14*x^2 + 9*x^3) / ((1 - x)*(1 + x)*(1 - 4*x + 2*x^2)). - _Colin Barker_, Jun 12 2018
%e Some solutions for n=4:
%e ..2..0..0....1..2..2....2..0..0....1..1..1....2..1..2....1..0..1....0..0..2
%e ..2..1..2....0..0..1....2..1..2....2..0..2....0..1..0....2..0..2....2..1..1
%e ..2..0..2....1..2..1....2..0..2....2..1..1....2..1..2....1..0..1....2..0..2
%e ..2..1..1....0..0..0....1..0..1....2..0..2....0..1..0....1..2..1....1..0..1
%e ..2..0..2....2..1..2....1..2..1....1..1..2....0..2..2....0..2..0....1..2..1
%Y Cf. A205823.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 01 2012
| 