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A232018
Number of n X 3 0..2 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.
1
9, 66, 852, 11517, 156913, 2125749, 28852936, 391447970, 5311170384, 72061691152, 977727048997, 13265735926493, 179988561188366, 2442072186590951, 33133863936280024, 449557939142907661, 6099570552966630306
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) + 59*a(n-2) + 62*a(n-3) - 275*a(n-4) - 257*a(n-5) + 146*a(n-6) + 84*a(n-7) for n>8.
Empirical g.f.: x*(9 - 15*x - 273*x^2 - 603*x^3 + 1375*x^4 + 1668*x^5 - 778*x^6 - 504*x^7) / (1 - 9*x - 59*x^2 - 62*x^3 + 275*x^4 + 257*x^5 - 146*x^6 - 84*x^7). - Colin Barker, Oct 01 2018
EXAMPLE
Some solutions for n=5:
..1..1..1....0..0..0....2..0..0....2..0..0....1..1..1....1..1..0....0..0..2
..0..0..0....1..0..0....0..0..0....0..2..2....0..0..0....1..0..2....0..0..1
..0..0..0....0..0..0....1..2..1....0..0..1....0..2..1....0..0..2....0..2..2
..2..0..1....0..2..0....1..1..0....0..0..0....0..0..0....0..0..0....2..1..1
..0..0..0....0..0..0....0..0..2....2..0..0....1..0..0....1..0..0....1..1..2
CROSSREFS
Column 3 of A232023.
Sequence in context: A226201 A091647 A321945 * A231199 A354532 A332456
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 17 2013
STATUS
approved