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.

3, 15, 51, 186, 687, 2485, 9068, 33308, 121445, 444183, 1626731, 5949198, 21774916, 79713938, 291767058, 1068145321, 3910543065, 14316731138, 52417430039, 191916565888, 702674552025, 2572785049162, 9420099176524, 34491356066515

Offset: 1

Author

R. H. Hardin, Nov 13 2013

Keywords

• nonn

Examples

			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
		

Links

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

Crossrefs

Column 2 of A231753.

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