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A223558
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Petersen graph (3,1) coloring a rectangular array: number of 3 X n 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,3 3,5 3,4 1,2 1,4 4,5 2,0 2,5 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph, with the array starting at 0.
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1
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36, 243, 3249, 44217, 609309, 8410671, 116124291, 1603350909, 22137868197, 305663255847, 4220371688499, 58271764766661, 804573346481541, 11108952552823119, 153384184751908707, 2117815160357837997
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 17*a(n-1) - 47*a(n-2) + 41*a(n-3) - 10*a(n-4) for n>6.
Empirical g.f.: 9*x*(4 - 41*x + 90*x^2 - 119*x^3 + 80*x^4 - 18*x^5) / ((1 - x)*(1 - 16*x + 31*x^2 - 10*x^3)). - Colin Barker, Aug 21 2018
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EXAMPLE
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Some solutions for n=3:
..0..2..0....0..3..0....0..1..4....0..3..4....0..3..5....0..1..2....0..1..0
..5..2..5....5..2..1....2..5..3....0..3..4....5..4..3....2..5..4....4..3..5
..5..3..5....5..4..3....4..5..2....0..3..4....3..0..3....2..1..4....0..3..4
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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