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Search: id:A166801
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| A166801 |
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Number of nX3 1..3 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 nondecreasing order. |
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+0
1
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| 1, 26, 134, 443, 1163, 2636, 5384, 10165, 18037, 30430, 49226, 76847, 116351, 171536, 247052, 348521, 482665, 657442, 882190, 1167779, 1526771
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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Empirical: a(n)=(n^6+9*n^5+70*n^4+135*n^3+64*n^2-279*n+90)/90
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EXAMPLE
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Some solutions for n=4
...1.1.1...1.1.2...1.2.2...1.1.3...1.1.1...1.1.1...1.2.2...1.1.3...1.2.3
...1.1.1...2.2.2...1.2.2...2.2.3...1.1.1...1.1.2...1.2.2...1.3.3...3.3.3
...1.1.3...2.3.2...3.3.3...2.2.3...1.1.3...2.2.2...2.2.2...2.2.3...3.3.3
...1.2.3...3.3.3...3.3.3...2.2.3...2.2.2...2.2.3...3.3.3...3.3.3...3.3.3
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...1.3.3...1.1.1...1.1.1...1.1.3...1.1.1...1.1.2...1.2.2...1.1.2...1.1.3
...1.3.3...1.1.3...1.2.2...1.2.2...1.2.2...1.2.2...1.2.3...2.2.2...1.2.3
...2.2.3...1.2.3...1.2.3...2.2.2...2.2.3...1.2.2...2.2.2...2.2.2...1.3.3
...2.3.3...1.2.3...2.2.3...2.2.2...3.3.3...3.3.3...2.2.2...2.3.3...3.3.3
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CROSSREFS
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Sequence in context: A166831 A042316 A042318 this_sequence A014552 A042314 A027280
Adjacent sequences: A166798 A166799 A166800 this_sequence A166802 A166803 A166804
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net) Oct 21 2009
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