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A166782 Number of n X 3 1..3 arrays containing at least one of each value, all equal values connected, and rows considered as a single number in nondecreasing order. 0
6, 90, 454, 1541, 4186, 9808, 20646, 40039, 72750, 125334, 206550, 327817, 503714, 752524, 1096822, 1564107, 2187478, 3006354, 4067238, 5424525, 7141354, 9290504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Empirical: a(n) = (11*n^6 + 57*n^5 + 545*n^4 + 285*n^3 + 1424*n^2 - 1782*n + 540)/180.

From G. C. Greubel, May 26 2016: (Start)

Empirical G.f.: x*(3*x^6 + x^5 - 7*x^4 + 43*x^3 - 50*x^2 + 48*x + 6 ) ) / (1-x)^7.

Empirical E.g.f.: (1/180)*(540 + 540*x + 7290*x^2 + 5970*x^3 + 1830*x^4 + 222*x^5 + 11*x^6)*exp(x) - 3. (End)

EXAMPLE

Some solutions for n=4:

...2.1.1...1.1.1...2.1.1...3.1.1...2.1.1...3.2.1...1.2.2...2.2.2...1.1.1

...2.2.2...1.1.1...3.3.1...3.1.1...2.2.2...3.2.1...3.2.3...3.2.1...1.1.1

...3.2.2...1.1.3...3.3.3...3.1.1...2.2.2...3.2.1...3.3.3...3.3.1...2.3.1

...3.3.2...1.2.2...3.3.3...3.2.1...3.3.2...3.3.3...3.3.3...3.3.1...3.3.3

------

...1.1.1...2.2.1...1.2.2...1.3.2...3.1.1...1.1.1...3.1.1...1.2.3...1.1.2

...3.2.1...2.2.2...2.2.2...1.3.2...3.2.2...1.1.3...3.1.1...1.2.3...1.1.3

...3.3.1...3.3.2...2.3.3...1.3.3...3.3.2...2.2.3...3.2.1...1.2.3...3.3.3

...3.3.1...3.3.3...3.3.3...1.3.3...3.3.3...2.2.3...3.2.2...1.3.3...3.3.3

CROSSREFS

Sequence in context: A100297 A177568 A177573 * A121249 A113404 A177283

Adjacent sequences:  A166779 A166780 A166781 * A166783 A166784 A166785

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 21 2009

STATUS

approved

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Last modified May 27 16:48 EDT 2022. Contains 354110 sequences. (Running on oeis4.)