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A223339
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5X5X5 triangular graph coloring a rectangular array: number of nX3 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 0,2 1,2 1,3 1,4 2,4 3,4 2,5 4,5 3,6 3,7 4,7 6,7 4,8 5,8 7,8 5,9 8,9 6,10 6,11 7,11 10,11 7,12 8,12 11,12 11,12 8,13 9,13 12,13 9,14 13,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph
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1
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264, 6696, 190740, 5514360, 161370036, 4730218284, 138947808456, 4081817304888, 119957730775764, 3525232400391672, 103605465347776488, 3044880491450389068, 89488169170132234404, 2630017284676266897204, 77295354555176007541020
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OFFSET
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1,1
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COMMENTS
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Column 3 of A223344
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 18*a(n-1) +585*a(n-2) -5160*a(n-3) -85485*a(n-4) +505600*a(n-5) +3996404*a(n-6) -19237700*a(n-7) -89239938*a(n-8) +375211256*a(n-9) +1104726794*a(n-10) -4232791939*a(n-11) -8081655126*a(n-12) +29153658888*a(n-13) +35808212649*a(n-14) -125320594701*a(n-15) -95870415823*a(n-16) +336725591045*a(n-17) +149825017362*a(n-18) -554412838812*a(n-19) -124734888118*a(n-20) +531808961051*a(n-21) +43836491896*a(n-22) -268190168640*a(n-23) -2736660827*a(n-24) +57764829598*a(n-25) +504580148*a(n-26) -3286957664*a(n-27) +156627216*a(n-28) +43946272*a(n-29) -3289536*a(n-30)
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EXAMPLE
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Some solutions for n=3
..7..4..3....3..7.12...11.12.11....1..3..4....7.12..7....7.11.12....7..8..5
..3..7..4....7..6..7...10.11..6....2..4..1...12..7..3....8.12.11....6..7..8
..7..4..2...12.11..6...11.12.11....4..2..4....7.12..7....7..8..7....3..6..7
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CROSSREFS
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Sequence in context: A092724 A112069 A282781 * A022043 A035315 A288877
Adjacent sequences: A223336 A223337 A223338 * A223340 A223341 A223342
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Mar 19 2013
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STATUS
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approved
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