|
%I #7 Oct 24 2018 10:10:48
%S 54,486,17496,408726,10789686,274834944,7073353350,181499433750,
%T 4661259221016,119679993219366,3073064486445414,78906460267708416,
%U 2026077840987433686,52023421931028414534,1335801507196609225944
%N Number of (n+1) X (3+1) 0..2 arrays with no element equal to all horizontal neighbors or equal to all vertical neighbors, and new values 0..2 introduced in row major order.
%H R. H. Hardin, <a href="/A238908/b238908.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 22*a(n-1) + 120*a(n-2) - 678*a(n-3) + 522*a(n-4) + 432*a(n-5) - 81*a(n-6).
%F Empirical g.f.: 54*x*(1 - 13*x + 6*x^2 + 39*x^3 - 9*x^4) / ((1 - 28*x + 60*x^2 - 9*x^3)*(1 + 6*x - 12*x^2 - 9*x^3)). - _Colin Barker_, Oct 24 2018
%e Some solutions for n=3:
%e ..0..1..2..1....0..1..2..0....0..1..0..1....0..1..0..1....0..1..0..2
%e ..1..0..1..2....1..2..1..2....2..0..1..2....1..0..1..0....2..0..1..0
%e ..0..2..0..2....0..2..1..0....0..2..1..0....0..1..1..2....2..1..1..0
%e ..2..1..2..1....2..1..0..1....2..0..0..1....2..0..0..1....1..0..2..1
%Y Column 3 of A238912.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 07 2014
| 