A231126 Number of (n+1) X (3+1) white-square subarrays of 0..2 arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.

6, 40, 308, 2260, 16812, 124644, 924900, 6862052, 50913012, 377747700, 2802692276, 20794524084, 154284599124, 1144711823796, 8493168927828, 63014915159220, 467538037568404, 3468890119531892, 25737368287958996, 190957944347003188

Offset: 1

Author

R. H. Hardin, Nov 04 2013

Keywords

• nonn

Comments

Column 3 of A231131.

Examples

			Some solutions for n=5:
..0..x..0..x....0..x..0..x....0..x..1..x....0..x..1..x....0..x..0..x
..x..1..x..2....x..1..x..2....x..2..x..0....x..2..x..2....x..1..x..0
..2..x..1..x....2..x..1..x....0..x..1..x....0..x..2..x....2..x..2..x
..x..0..x..2....x..0..x..0....x..0..x..1....x..1..x..0....x..0..x..2
..1..x..2..x....1..x..1..x....1..x..2..x....1..x..2..x....0..x..1..x
..x..2..x..1....x..0..x..0....x..1..x..1....x..2..x..1....x..2..x..2
		

Links

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

Crossrefs

Cf. A231131.

Formula

Empirical: a(n) = 7*a(n-1) + 8*a(n-2) - 32*a(n-3) - 38*a(n-4) + 40*a(n-5) + 56*a(n-6) - 16*a(n-7) - 16*a(n-8).

Empirical g.f.: 2*x*(3 - x - 10*x^2 - 12*x^3 + 18*x^4 + 8*x^5 - 8*x^6) / (1 - 7*x - 8*x^2 + 32*x^3 + 38*x^4 - 40*x^5 - 56*x^6 + 16*x^7 + 16*x^8). - Colin Barker, Mar 18 2018