A166762 Number of nX3 1..3 arrays containing at least one of each value, and all equal values connected.

6, 174, 1548, 8100, 32208, 108456, 327042, 912330, 2403570, 6063738, 14792208, 35140296, 81722988, 186803940, 420988854, 937659294, 2067934782, 4522786278, 9821642100, 21198358092, 45510675048, 97254168192, 206980215882

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Formula

Empirical: a(n) = 11*a(n-1) - 53*a(n-2) + 147*a(n-3) - 259*a(n-4) + 301*a(n-5) - 231*a(n-6) + 113*a(n-7) - 32*a(n-8) + 4*a(n-9).

Example

Some solutions for n=4
...2.2.2...2.2.3...1.1.1...1.1.2...1.2.2...1.1.1...2.2.3...2.3.3...3.3.3
...1.1.2...3.2.3...3.1.1...2.2.2...3.3.2...1.3.3...2.3.3...2.3.1...3.1.1
...3.1.2...3.3.3...2.2.1...3.2.2...3.3.2...1.1.1...1.1.3...2.3.1...2.1.2
...3.1.1...3.1.3...1.1.1...3.3.3...2.2.2...2.2.1...1.1.1...2.1.1...2.2.2
------
...1.1.2...2.2.2...1.1.1...1.1.1...3.3.3...3.3.3...2.2.2...3.3.1...2.1.3
...1.1.1...1.1.3...1.1.1...2.1.1...3.3.1...1.3.3...3.2.1...2.3.1...1.1.3
...1.3.3...3.3.3...2.3.1...2.1.3...2.3.3...1.1.3...3.3.1...2.3.3...1.1.1
...1.1.3...3.3.3...2.3.1...1.1.3...2.2.2...1.2.2...1.1.1...2.3.3...1.1.1

Crossrefs

Sequence in context: A266311 A323820 A317795 * A323279 A214801 A233225

Adjacent sequences: A166759 A166760 A166761 * A166763 A166764 A166765

Keyword

nonn

Author

R. H. Hardin, Oct 21 2009

Status

approved