login
A166779
Number of nX2 1..6 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, 120, 2280, 15266, 65553, 217460, 607565, 1499964, 3370950, 7034048, 13819102, 25822302, 46247695, 79864876, 133612235, 217380376, 345016156, 535594248, 815010244
OFFSET
1,3
FORMULA
From G. C. Greubel, May 26 2016: (Start)
Empirical a(n) = (1/226800)*(n-1)*(n-2)*(2*n^8 + 106*n^7 + 2819*n^6 + 41065*n^5 + 264893*n^4 + 73939*n^3 - 3091374*n^2 + 1937430*n - 113400).
Empirical G.f.: x^3*(x^8 + 121*x^7 - 664*x^6 + 1010*x^5 + 593*x^4 - 3227*x^3 + 3214*x^2 - 960*x - 120)/(x-1)^11.
Empirical E.g.f.: (1/226800)*(-226800 + 226800*x - 113400*x^2 + 4573800*x^3 + 17000550*x^4 + 9576630*x^5 + 1813140*x^6 + 160920*x^7 + 7605*x^8 + 190*x^9 + 2*x^10)*exp(x) + 1. (End)
EXAMPLE
Some solutions for n=4
...3.2...4.1...2.4...3.5...2.1...2.2...1.5...1.4...1.1...1.4...4.1...2.2...4.4
...3.6...4.2...2.4...4.4...2.4...3.6...2.6...2.5...1.4...2.4...4.3...3.3...5.3
...4.1...4.3...5.1...6.1...3.5...4.1...3.3...3.3...3.6...3.5...5.2...5.1...6.1
...5.5...6.5...6.3...6.2...3.6...5.1...4.4...3.6...5.2...6.6...5.6...6.4...6.2
------
...1.5...2.6...1.3...1.2...2.3...1.3...2.6...1.5...2.5...1.2...3.1...5.1...2.1
...2.4...3.3...1.6...3.3...5.1...5.5...3.1...6.2...4.3...3.5...4.2...5.3...2.1
...4.4...3.4...2.2...4.5...5.5...6.2...4.5...6.3...4.4...3.6...5.2...5.4...4.5
...6.3...5.1...5.4...6.5...6.4...6.4...5.5...6.4...6.1...4.6...6.2...6.2...6.3
CROSSREFS
Sequence in context: A084030 A056291 A056286 * A038745 A267839 A220050
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 21 2009
STATUS
approved