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A223420 3-level binary fanout graph coloring a rectangular array: number of nX5 0..6 arrays where 0..6 label nodes of a graph with edges 0,1 1,3 1,4 0,2 2,5 2,6 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

%I A223420 #6 Jul 23 2025 04:07:57
%S A223420 104,1584,29912,486016,9210784,150006016,2844612736,46345527296,
%T A223420 878977950208,14321836797952,271631946213376,4425979070611456,
%U A223420 83944852851777536,1367805247361974272,25942363680265961472
%N A223420 3-level binary fanout graph coloring a rectangular array: number of nX5 0..6 arrays where 0..6 label nodes of a graph with edges 0,1 1,3 1,4 0,2 2,5 2,6 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.
%C A223420 Column 5 of A223423
%H A223420 R. H. Hardin, <a href="/A223420/b223420.txt">Table of n, a(n) for n = 1..210</a>
%F A223420 Empirical: a(n) = 392*a(n-2) -26768*a(n-4) +353408*a(n-6) -1274624*a(n-8) +1441792*a(n-10) -307200*a(n-12) for n>13
%e A223420 Some solutions for n=3
%e A223420 ..0..2..6..2..6....2..6..2..0..2....0..1..3..1..3....0..2..0..2..6
%e A223420 ..2..5..2..0..2....0..2..0..1..0....1..3..1..4..1....2..0..2..5..2
%e A223420 ..0..2..5..2..0....2..0..1..3..1....4..1..0..1..0....0..2..6..2..5
%K A223420 nonn
%O A223420 1,1
%A A223420 _R. H. Hardin_ Mar 20 2013