A166828 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 nonincreasing order.

0, 0, 30, 728, 5364, 24402, 84285, 242793, 614140, 1407960, 2987500, 5953706, 11263472, 20392138, 35552387, 59984019, 98331688, 157130592, 245423322

Offset

1,3

Links

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

Formula

From G. C. Greubel, May 25 2016: (Start)

Empirical: a(n) = (16/(10)!)*(n-1)*(n-2)*(n^8 + 53*n^7 + 1342*n^6 + 17630*n^5 + 91114*n^4 - 102013*n^3 - 1246977*n^2 + 1575810*n - 113400).

Empirical G.f.: (1 - 11*x + 55*x^2 - 195*x^3 - 68*x^4 + 532*x^5 - 26*x^6 - 993*x^7 + 1077*x^8 - 461*x^9 + 73*x^10)/(x -1)^11 + 1.

Empirical E.g.f.: (16/(10)!)*(-226800 + 226800*x - 113400*x^2 + 1171800*x^3 + 5736150*x^4 + 3827250*x^5 + 799155*x^6 + 75870*x^7 + 3735*x^8 + 95*x^9 + x^10)*exp(x) + 1. (End)

Example

All solutions for n=3
...4.3...4.3...3.1...3.1...3.1...3.1...3.2...3.2...3.2...3.2...3.1...3.1...3.2
...5.1...5.2...4.2...4.2...4.5...4.6...4.1...4.1...4.5...4.6...5.4...5.2...5.4
...6.2...6.1...5.6...6.5...6.2...5.2...5.6...6.5...6.1...5.1...6.2...6.4...6.1
------
...3.2...4.1...4.1...4.2...4.2...2.1...2.1...2.1...2.1...2.1...2.1...2.1...2.1
...5.1...5.3...5.2...5.3...5.1...3.4...3.4...3.5...3.5...3.6...3.6...4.3...4.3
...6.4...6.2...6.3...6.1...6.3...5.6...6.5...6.4...4.6...5.4...4.5...5.6...6.5
------
...2.1...2.1...2.1...2.1
...4.5...4.6...5.3...5.4
...6.3...5.3...6.4...6.3

Crossrefs

Sequence in context: A035520 A122186 A166840 * A053509 A273435 A259345

Adjacent sequences: A166825 A166826 A166827 * A166829 A166830 A166831

Keyword

nonn,more

Author

R. H. Hardin, Oct 21 2009

Status

approved