A232042 - OEIS

A232042

Number of n X 3 0..1 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.

4, 15, 80, 446, 2477, 13752, 76375, 424115, 2355221, 13079032, 72630752, 403334385, 2239803950, 12438120321, 69071597937, 383569664377, 2130046094920, 11828611039210, 65686859759121, 364773474308192, 2025666747456127

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) + 9*a(n-2) -a (n-3) - 6*a(n-4) for n>5.

Empirical g.f.: x*(4 - x - 16*x^2 - 5*x^3 + 12*x^4) / (1 - 4*x - 9*x^2 + x^3 + 6*x^4). - Colin Barker, Oct 02 2018

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 3 of A232047.

Sequence in context: A179511 A111726 A090376 * A125307 A073479 A147690

Adjacent sequences: A232039 A232040 A232041 * A232043 A232044 A232045

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 17 2013

STATUS

approved