A232583 Number of (n+1)X(2+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally or antidiagonally, with no adjacent elements equal.

10, 34, 124, 456, 1686, 6232, 23034, 85130, 314626, 1162804, 4297528, 15882942, 58700688, 216947890, 801802986, 2963329250, 10951967500, 40476633544, 149594843398, 552877431048, 2043342182250, 7551849721642, 27910368960066

Offset: 1

Author

R. H. Hardin, Nov 26 2013

Keywords

• nonn

Comments

Column 2 of A232589

Examples

			Some solutions for n=7
..0..1..2....2..1..2....0..1..2....0..1..2....2..1..2....0..1..0....2..1..0
..0..1..2....0..1..2....2..1..0....0..1..0....0..1..0....2..1..2....2..1..2
..0..1..0....2..1..0....0..1..2....2..1..2....2..1..2....2..1..0....0..1..2
..2..1..2....2..1..0....0..1..2....0..1..2....2..1..0....0..1..0....2..1..2
..0..1..0....0..1..0....2..1..2....2..1..0....2..1..0....2..1..2....0..1..0
..2..1..2....2..1..0....0..1..0....0..1..2....0..1..2....2..1..0....0..1..2
..2..1..2....0..1..2....2..1..0....0..1..0....2..1..0....0..1..2....0..1..2
..0..1..0....0..1..0....2..1..0....2..1..0....2..1..0....0..1..2....0..1..2
		

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -a(n-2) -a(n-3) +2*a(n-4).

Empirical: G.f.: -2*x*(5-3*x-x^2+2*x^3) / ( -1+4*x-x^2-x^3+2*x^4 ). - R. J. Mathar, Nov 23 2014