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A166817 Number of n X 2 1..6 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 increasing order. 0
0, 0, 90, 1552, 9902, 41151, 133175, 364772, 885824, 1962990, 4046548, 7865396, 14558830, 25855557, 44312489, 73628216, 119048688, 187885564, 290170926 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..19.

FORMULA

Empirical: a(n) = (16/10!)*n*(n-1)*(n-2)*(361620 - 1844397*n + 175952*n^2 + 173779*n^3 + 23435*n^4 + 1477*n^5 + 53*n^6 + n^7). - G. C. Greubel, May 25 2016

Empirical g.f.: x^3*(90+562*x-2220*x^2+2739*x^3-1256*x^4-98*x^5+258*x^6-59*x^7) / (1-x)^11. - Colin Barker, May 25 2016

EXAMPLE

Some solutions for n=4

...1.5...1.4...2.3...1.1...2.6...1.1...1.2...1.3...1.3...2.4...1.1...1.4...3.6

...4.2...2.6...5.1...2.4...4.3...1.3...3.3...5.2...2.4...5.3...1.5...5.2...4.1

...4.2...3.3...5.4...3.5...4.3...2.5...4.6...5.4...2.6...5.5...3.4...5.3...4.2

...6.3...5.5...5.6...6.6...5.1...4.6...5.6...6.4...5.6...6.1...6.2...5.6...5.2

------

...1.2...2.5...1.6...1.6...1.5...1.2...2.4...2.4...1.1...1.4...1.4...2.3...1.4

...2.2...4.1...2.2...4.3...3.2...1.5...2.4...2.4...1.4...2.5...2.2...2.3...2.2

...3.5...6.3...3.4...5.2...3.2...6.3...3.6...3.1...3.5...3.5...2.5...4.1...2.5

...6.4...6.6...5.5...5.2...6.4...6.4...5.1...6.5...6.2...6.6...6.3...5.6...3.6

CROSSREFS

Sequence in context: A279438 A250869 A234983 * A166799 A001561 A296998

Adjacent sequences: A166814 A166815 A166816 * A166818 A166819 A166820

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 21 2009

STATUS

approved

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Last modified January 28 08:03 EST 2023. Contains 359850 sequences. (Running on oeis4.)