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A166778 Number of nX2 1..5 arrays containing at least one of each value, all equal values connected, and rows considered as a single number in nondecreasing order. 0
0, 0, 160, 1245, 5326, 16876, 44382, 102609, 215668, 421056, 774852, 1358269, 2285778, 3715036, 5858866, 8999553, 13505736, 19852192, 28642824, 40637181, 56780854, 78240108, 106441126, 143114257, 190343676, 250622880 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
FORMULA
Empirical: a(n) = (1/2520)*(n-1)*(n-2)*(n^6 + 35*n^5 + 551*n^4 + 4033*n^3 + 8106*n^2 -11790*n + 1260).
From G. C. Greubel, May 26 2016: (Start)
Empirical G.f.: x^3*(x^6 + 33*x^5 - 186*x^4 + 322*x^3 - 119*x^2 - 195*x + 160) ) /(1-x)^9.
Empirical E.g.f.: (1/2520)*(2520 - 2520*x + 1260*x^2 + 66780*x^3 + 63630*x^4 + 14700*x^5 + 1386*x^6 + 60*x^7 + x^8)*exp(x) - 1. (End)
EXAMPLE
Some solutions for n=4
...1.3...1.3...3.2...1.1...2.1...2.1...2.1...1.3...2.2...1.3...3.1...4.2...1.3
...2.3...1.4...4.1...3.3...2.4...2.3...2.4...2.5...2.4...2.3...3.3...4.3...1.3
...2.3...2.5...4.4...4.4...5.3...3.3...3.3...4.5...3.1...5.4...4.3...5.1...2.5
...5.4...2.5...5.5...5.2...5.3...5.4...5.5...5.5...5.5...5.5...5.2...5.1...4.4
------
...2.2...1.1...1.1...2.2...1.1...1.1...1.1...1.3...1.1...2.1...2.3...1.3...1.1
...4.4...2.4...2.5...2.4...1.2...3.1...1.1...2.4...1.2...3.3...4.4...1.3...4.2
...5.1...3.4...3.3...3.4...4.4...3.5...2.5...4.4...1.4...3.4...5.1...2.4...5.3
...5.3...3.5...4.4...5.1...5.3...4.2...3.4...5.4...3.5...3.5...5.1...5.5...5.3
CROSSREFS
Sequence in context: A305272 A234450 A234444 * A236518 A120103 A235655
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 21 2009
STATUS
approved

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Last modified July 19 11:15 EDT 2024. Contains 374392 sequences. (Running on oeis4.)