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A166838
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Number of nX2 1..4 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in decreasing order.
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1
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0, 4, 49, 218, 662, 1626, 3479, 6748, 12156, 20664, 33517, 52294, 78962, 115934, 166131, 233048, 320824, 434316, 579177, 761938, 990094, 1272194, 1617935, 2038260, 2545460, 3153280, 3877029, 4733694, 5742058, 6922822, 8298731, 9894704
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OFFSET
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1,2
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LINKS
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FORMULA
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Empirical: a(n) = (n^6 + 18*n^5 + 100*n^4 - 30*n^3 - 551*n^2 + 462*n)/180.
Empirical G.f.: x^2*(4 + 21*x - 41*x^2 + 25*x^3 - 5*x^4)/(1 - x)^7.
Empirical E.g.f.: (1/180)*x^2*(360 + 1110*x + 345*x^2 + 33*x^3 + x^4)*exp(x). (End)
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EXAMPLE
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All solutions for n=3
...1.1...1.1...1.1...1.1...1.1...1.1...1.1...1.1...1.1...2.1...2.1...2.1...2.1
...2.1...2.1...2.2...3.1...3.2...3.2...3.2...3.3...4.2...2.1...2.1...2.2...2.2
...3.4...4.3...4.3...4.2...3.4...4.2...4.4...4.2...4.3...3.4...4.3...3.4...4.3
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...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1
...2.3...2.3...2.3...2.4...2.4...3.1...3.1...3.1...3.3...3.3...3.3...3.4...3.4
...2.4...4.3...4.4...3.3...3.4...3.4...4.1...4.4...3.4...4.3...4.4...3.4...4.4
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...2.1...2.1...2.1...2.2...2.2...2.2...2.2...2.2...2.2...3.1...3.1...3.1...3.1
...4.1...4.3...4.3...3.1...3.1...3.1...3.2...3.3...4.1...3.1...3.2...3.2...3.2
...4.3...4.3...4.4...3.4...4.1...4.4...4.1...4.1...4.3...4.2...3.4...4.2...4.4
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...3.1...3.1...3.1...3.1...3.2...3.2...3.2...3.2...3.3...4.1
...3.3...4.1...4.2...4.2...3.2...3.3...4.1...4.1...4.1...4.2
...4.2...4.2...4.2...4.4...4.1...4.1...4.1...4.4...4.2...4.3
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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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