A183597 1/6 the number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock containing all three values.

120, 1479, 17174, 201770, 2366412, 27768032, 325834456, 3823553752, 44868561272, 526526214848, 6178727749808, 72506794636336, 850861000923008, 9984783537547136, 117170625132737568, 1374987868096008576

Offset: 1

Author

R. H. Hardin, Jan 05 2011

Keywords

• nonn

Comments

Column 3 of A183603.

Examples

			Some solutions with a(1,1)=0 for 3 X 4:
..0..2..2..1....0..0..0..0....0..1..2..0....0..0..0..1....0..1..2..1
..2..1..0..2....2..1..2..1....2..0..1..0....2..1..2..2....2..2..0..0
..0..0..2..1....2..0..2..0....0..1..2..1....0..1..0..1....1..0..1..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A183603.

Formula

Empirical: a(n) = 12*a(n-1) + 20*a(n-2) - 238*a(n-3) - 420*a(n-4) + 324*a(n-5) + 400*a(n-6) - 224*a(n-7).

Empirical g.f.: x*(120 + 39*x - 2974*x^2 - 5338*x^3 + 4094*x^4 + 5400*x^5 - 3024*x^6) / (1 - 12*x - 20*x^2 + 238*x^3 + 420*x^4 - 324*x^5 - 400*x^6 + 224*x^7). - Colin Barker, Mar 30 2018