A166819 - OEIS

%I #3 Mar 31 2012 12:35:36

%S 1,14,83,308,877,2106,4487,8744,15897,27334,44891,70940,108485,161266,

%T 233871,331856,461873,631806,850915,1129988,1481501

%N Number of nX3 1..3 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.

%F Empirical: a(n)=(n^6+9*n^5+55*n^4+15*n^3-56*n^2+66*n)/90

%e Some solutions for n=4

%e ...1.1.1...1.1.1...1.1.1...1.3.3...1.2.2...1.1.3...1.1.1...1.1.3...1.1.1

%e ...1.2.2...1.1.2...1.2.3...2.2.3...2.2.3...1.1.3...1.1.2...1.2.2...1.1.2

%e ...2.2.3...1.2.2...1.2.3...2.3.3...2.2.3...2.2.3...1.2.2...2.2.2...1.3.2

%e ...3.3.3...3.3.2...2.2.3...3.3.3...2.2.3...2.3.3...1.3.2...2.2.2...1.3.2

%e ------

%e ...1.2.3...1.1.1...1.2.2...1.1.3...1.2.3...1.1.2...1.1.1...1.1.1...1.1.2

%e ...1.2.3...1.1.3...1.2.2...1.2.3...1.2.3...2.2.2...1.2.3...1.2.2...1.2.2

%e ...1.2.3...2.2.3...1.2.2...1.3.3...1.3.3...2.3.2...1.2.3...1.2.3...1.3.2

%e ...2.2.3...2.3.3...2.2.3...1.3.3...1.3.3...3.3.3...3.3.3...3.3.3...3.3.2

%K nonn

%O 1,2

%A _R. H. Hardin_ Oct 21 2009