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A233128 Number of nX7 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).

%I A233128 #6 Jun 02 2025 08:51:10
%S A233128 528,1495040,4653056000,14800557965312,47441169369530368,
%T A233128 152534173898504142848,491056502853059022422016,
%U A233128 1581710916068322391195910144,5095889238903796606027591319552
%N A233128 Number of nX7 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 A233128 Column 7 of A233129
%H A233128 R. H. Hardin, <a href="/A233128/b233128.txt">Table of n, a(n) for n = 1..210</a>
%F A233128 Empirical: a(n) = 7168*a(n-1) -19070976*a(n-2) +26086473728*a(n-3) -21081846972416*a(n-4) +10809917287956480*a(n-5) -3649692508960587776*a(n-6) +824336623994081902592*a(n-7) -124561639357723747287040*a(n-8) +12414326720213201465638912*a(n-9) -792885332473813431379558400*a(n-10) +31062140009178282014900486144*a(n-11) -704387882353381376417601683456*a(n-12) +8398185226512019784915658735616*a(n-13) -40564819207303340847894502572032*a(n-14)
%e A233128 Some solutions for n=1
%e A233128 ..0..1..0..4..5..4..5....0..1..0..4..5..1..5....0..1..0..2..0..4..2
%K A233128 nonn
%O A233128 1,1
%A A233128 _R. H. Hardin_, Dec 04 2013