A233156 Number of 3 X n 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally or antidiagonally.

27, 96, 432, 1944, 8856, 40392, 184248, 840456, 3833784, 17488008, 79772472, 363886344, 1659886776, 7571661192, 34538532408, 157549339656, 718669633464, 3278249488008, 14953908173112, 68213041889544, 311157393101496

Offset: 1

Author

R. H. Hardin, Dec 05 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A233155.

Formula

Empirical: a(n) = 5*a(n-1) - 2*a(n-2) for n>4.

Empirical g.f.: 3*x*(9 - 13*x + 2*x^2 - 8*x^3) / (1 - 5*x + 2*x^2). - Colin Barker, Oct 09 2018