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 A233125 Number of nX4 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or vertically, 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) 1

%I

%S 10,896,96256,10674176,1189609472,132682612736,14800557965312,

%T 1651015493353472,184172904936636416,20544737466392772608,

%U 2291793599167553601536,255652719756086620454912

%N Number of nX4 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or vertically, 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)

%C Column 4 of A233129

%H R. H. Hardin, <a href="/A233125/b233125.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 160*a(n-1) -6144*a(n-2) +86016*a(n-3) -393216*a(n-4).

%F Empirical: G.f.: -2*x*(-5+352*x-7168*x^2+40960*x^3) / ( (16*x-1)*(24576*x^3-3840*x^2+144*x-1) ). - _R. J. Mathar_, Oct 31 2015

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 04 2013

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Last modified June 22 17:18 EDT 2021. Contains 345388 sequences. (Running on oeis4.)