login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A219349 Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 n X 3 array. 1
3, 3, 8, 15, 27, 46, 76, 122, 190, 287, 421, 601, 837, 1140, 1522, 1996, 2576, 3277, 4115, 5107, 6271, 7626, 9192, 10990, 13042, 15371, 18001, 20957, 24265, 27952, 32046, 36576, 41572, 47065, 53087, 59671, 66851, 74662, 83140, 92322, 102246, 112951 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A219354.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = (1/24)*n^4 - (1/4)*n^3 + (23/24)*n^2 + (13/4)*n - 8 for n > 3.

Conjectures from Colin Barker, Jul 25 2018: (Start)

G.f.: x*(3 - 12*x + 23*x^2 - 25*x^3 + 17*x^4 - 7*x^5 + 3*x^6 - x^7) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 8.

(End)

EXAMPLE

Some solutions for n=3:

  0 0 0   0 0 0   0 0 0   0 0 1   0 0 0   1 1 1   0 0 1

  0 0 0   0 0 0   0 0 0   0 0 1   0 0 0   1 1 1   0 0 1

  0 0 0   0 0 1   1 1 1   1 1 1   1 0 0   1 1 1   0 0 1

CROSSREFS

Cf. A219354.

Sequence in context: A126592 A055057 A154029 * A208964 A104864 A300367

Adjacent sequences:  A219346 A219347 A219348 * A219350 A219351 A219352

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 18 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 18 07:11 EDT 2019. Contains 326072 sequences. (Running on oeis4.)