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A231747 Number of n X 2 0..2 arrays with no element less than a strict majority of its horizontal, vertical, diagonal and antidiagonal neighbors. 1
3, 15, 51, 186, 687, 2485, 9068, 33308, 121445, 444183, 1626731, 5949198, 21774916, 79713938, 291767058, 1068145321, 3910543065, 14316731138, 52417430039, 191916565888, 702674552025, 2572785049162, 9420099176524, 34491356066515 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 3*a(n-2) + 14*a(n-3) - 39*a(n-4) - 45*a(n-5) - 124*a(n-6) + 18*a(n-7) + 132*a(n-8) + 248*a(n-9) + 112*a(n-10) + 64*a(n-11).

Empirical g.f.: x*(3 + 6*x - 3*x^2 - 54*x^3 - 117*x^4 - 128*x^5 - 16*x^6 + 386*x^7 + 348*x^8 + 224*x^9 + 64*x^10) / (1 - 3*x - 3*x^2 - 14*x^3 + 39*x^4 + 45*x^5 + 124*x^6 - 18*x^7 - 132*x^8 - 248*x^9 - 112*x^10 - 64*x^11). - Colin Barker, Sep 30 2018

EXAMPLE

Some solutions for n=7:

..1..0....2..2....0..2....0..0....1..0....2..1....0..0....0..0....2..0....0..2

..0..0....1..1....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0

..0..0....1..1....0..0....0..0....0..0....0..0....0..1....1..2....0..0....0..0

..0..0....1..1....2..1....1..1....0..0....0..0....0..0....1..1....0..2....0..1

..1..2....2..1....0..0....2..1....1..1....0..0....0..0....1..2....0..0....0..2

..1..1....2..1....0..0....1..1....1..1....2..0....2..1....1..1....0..0....0..0

..1..1....1..1....1..0....1..2....1..1....0..0....1..1....1..2....0..2....0..2

CROSSREFS

Column 2 of A231753.

Sequence in context: A118126 A282464 A284663 * A192742 A166035 A038192

Adjacent sequences:  A231744 A231745 A231746 * A231748 A231749 A231750

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 2013

STATUS

approved

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Last modified September 28 06:57 EDT 2021. Contains 347703 sequences. (Running on oeis4.)