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A233172 Number of nX6 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally, diagonally 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).

%I A233172 #6 Jun 02 2025 08:51:32
%S A233172 136,92672,76447744,65265467392,56275748519936,48667983827959808,
%T A233172 42129429039341895680,36480870847649836695552,
%U A233172 31592958742989872646062080,27360904144981190573706706944,23696028949244230878346703011840
%N A233172 Number of nX6 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally, diagonally 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).
%C A233172 Column 6 of A233174
%H A233172 R. H. Hardin, <a href="/A233172/b233172.txt">Table of n, a(n) for n = 1..210</a>
%F A233172 Empirical: a(n) = 1216*a(n-1) -303104*a(n-2) -6553600*a(n-3) +6056574976*a(n-4) -287762808832*a(n-5) -18622978195456*a(n-6) +1482141674242048*a(n-7) -15199648742375424*a(n-8) -522417556774977536*a(n-9) +5764607523034234880*a(n-10)
%e A233172 Some solutions for n=2
%e A233172 ..0..1..5..2..5..1....0..1..2..1..2..1....0..1..5..1..0..4....0..1..0..2..1..2
%e A233172 ..5..2..5..3..0..2....5..1..5..1..5..4....5..1..0..2..5..1....5..1..0..2..1..2
%K A233172 nonn
%O A233172 1,1
%A A233172 _R. H. Hardin_, Dec 05 2013