A233258 - OEIS

%I #8 Oct 11 2018 05:40:09

%S 11,136,4672,166400,6049792,220626944,8050180096,293762760704,

%T 10720053821440,391200251052032,14275841005453312,520959990903603200,

%U 19011091850007150592,693760794065113186304,25317011997007519154176

%N Number of 3 X n 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).

%H R. H. Hardin, <a href="/A233258/b233258.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 48*a(n-1) - 448*a(n-2) + 1024*a(n-3) for n>5.

%F Empirical g.f.: x*(11 - 392*x + 3072*x^2 - 8192*x^3 + 16384*x^4) / ((1 - 8*x)*(1 - 40*x + 128*x^2)). - _Colin Barker_, Oct 11 2018

%e Some solutions for n=3:

%e ..0..1..5....0..1..5....0..1..2....0..1..2....0..1..2....0..1..2....0..1..2

%e ..5..2..5....5..2..0....3..1..3....0..4..5....2..5..3....3..1..5....5..1..2

%e ..1..3..5....4..2..0....5..1..2....0..2..4....1..0..2....5..4..3....5..4..0

%Y Row 3 of A233256.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 06 2013