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A166759 Number of nX2 1..6 arrays containing at least one of each value, and all equal values connected. 0
0, 0, 720, 32400, 434160, 3309120, 17807040, 75294000, 266274720, 819872640, 2259483120, 5685633360, 13259846160, 28992150720, 59970549600, 118213974000, 223381776960 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..17.

FORMULA

From G. C. Greubel, May 26 2016: (Start)

Empirical a(n) = (2/315)*(n-1)*(n-2)*(32*n^8 - 304*n^7 + 2744*n^6 - 15880*n^5 + 62078*n^4 - 171871*n^3 + 319311*n^2 - 353880*n + 170100).

Empirical G.f.: 720*x^3*(3*x+1)*(x^7 + 8*x^6 + 25*x^5 + 57*x^4 + 63*x^3 + 70*x^2 + 31*x + 1)/(1-x)^11.

Empirical E.g.f.: (2/315)*(340200 - 340200*x + 170100*x^2 - 37800*x^3 + 207900*x^4 + 363825*x^5 + 257670*x^6 + 82800*x^7 + 13320*x^8 + 1040*x^9 + 32*x^10)*exp(x) - 2160. (End)

EXAMPLE

Some solutions for n=3

...4.1...1.4...2.5...5.2...6.4...4.6...3.6...3.2...3.5...2.6...2.5...1.2...4.1

...6.5...5.2...4.3...3.6...5.3...1.2...4.1...6.5...6.2...4.1...3.1...5.3...6.3

...3.2...6.3...1.6...1.4...2.1...5.3...2.5...1.4...1.4...3.5...6.4...4.6...5.2

------

...3.2...5.3...1.5...5.4...1.6...2.6...1.6...1.3...4.1...6.4...6.4...3.4...3.6

...4.5...4.1...3.6...1.6...4.5...3.4...5.2...2.6...5.6...3.2...1.3...6.2...4.1

...1.6...2.6...2.4...3.2...2.3...5.1...4.3...4.5...2.3...1.5...2.5...1.5...5.2

CROSSREFS

Sequence in context: A223857 A003938 A052720 * A181504 A179061 A342074

Adjacent sequences: A166756 A166757 A166758 * A166760 A166761 A166762

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 21 2009

STATUS

approved

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Last modified December 9 11:21 EST 2022. Contains 358700 sequences. (Running on oeis4.)