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 A166786 Number of nX4 1..2 arrays containing at least one of each value, all equal values connected, and rows considered as a single number in nondecreasing order. 0

%I

%S 6,31,112,317,750,1559,2944,5165,8550,13503,20512,30157,43118,60183,

%T 82256

%N Number of nX4 1..2 arrays containing at least one of each value, all equal values connected, and rows considered as a single number in nondecreasing order.

%F Empirical: a(n) = (2*n^5 + 15*n^4 + 60*n^3 - 75*n^2 + 268*n - 90)/30.

%F From _G. C. Greubel_, May 26 2016: (Start)

%F Empirical G.f.: x*(3*x^5 - 2*x^4 - 10*x^3 + 16*x^2 - 5*x + 6)/(1-x)^6.

%F Empirical E.g.f.: (1/30)*(-90 + 270*x + 240*x^2 + 200*x^3 + 35*x^4 + 2*x^5)*exp(x) + 3. (End)

%e Some solutions for n=4

%e ...1.1.1.1...1.1.1.1...1.1.2.2...1.1.2.2...1.1.1.1...1.1.1.1...1.1.1.1

%e ...2.1.1.1...2.2.2.2...2.1.1.2...1.1.2.2...2.1.1.2...1.1.2.1...2.1.1.1

%e ...2.2.1.1...2.2.2.2...2.2.1.2...1.1.2.2...2.1.1.2...1.1.2.2...2.1.1.1

%e ...2.2.2.2...2.2.2.2...2.2.2.2...2.2.2.2...2.2.2.2...1.2.2.2...2.2.1.1

%e ------

%e ...1.1.1.1...1.1.1.1...1.1.1.2...1.1.1.1...2.1.1.1...1.1.1.1...1.1.1.2

%e ...1.1.1.2...1.2.1.1...1.1.1.2...1.1.1.1...2.1.1.1...2.1.2.1...1.2.1.2

%e ...1.2.2.2...1.2.1.1...2.2.2.2...1.2.2.2...2.2.1.1...2.1.2.2...1.2.1.2

%e ...2.2.2.2...2.2.2.1...2.2.2.2...1.2.2.2...2.2.2.1...2.2.2.2...1.2.2.2

%K nonn,more

%O 1,1

%A _R. H. Hardin_, Oct 21 2009

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