A232957 Number of 3 X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, diagonally or antidiagonally, and top left element zero.

16, 147, 1881, 22971, 283131, 3484893, 42904365, 528197043, 6502696923, 80055386493, 985570487037, 12133464037491, 149376378762507, 1838988638568957, 22639986598509837, 278723306070050355

Offset: 1

Author

R. H. Hardin, Dec 02 2013

Keywords

• nonn

Examples

			Some solutions for n=4:
..0..0..1..1....0..0..0..0....0..1..0..0....0..1..1..1....0..1..1..1
..0..1..1..0....1..1..1..1....0..1..1..0....3..1..1..3....0..0..0..1
..0..0..0..1....1..0..1..0....0..0..1..1....3..1..3..1....1..1..1..0
		

Links

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

Crossrefs

Row 3 of A232955.

Formula

Empirical: a(n) = 12*a(n-1) + 7*a(n-2) - 40*a(n-3) + 12*a(n-4).

Empirical g.f.: x*(16 - 45*x + 5*x^2 + 10*x^3) / (1 - 12*x - 7*x^2 + 40*x^3 - 12*x^4). - Colin Barker, Oct 06 2018