A229690 Number of defective 3-colorings of an nX4 0..2 array connected horizontally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.

3, 245, 5077, 80757, 1125333, 14461173, 175867605, 2054728053, 23284024533, 257577229557, 2794463987157, 29833314755445, 314218549864917, 3271569607417077, 33725758239805653, 344669380723927413

Offset: 1

Author

R. H. Hardin, Sep 27 2013

Keywords

• nonn

Comments

Column 4 of A229694

Examples

			Some solutions for n=3
..0..0..1..0....0..1..0..2....0..1..2..0....0..1..2..1....0..1..0..2
..1..0..1..2....2..1..0..0....0..1..0..2....0..2..0..2....2..1..0..1
..1..0..0..2....2..0..1..2....0..1..2..1....0..1..1..2....2..0..0..1
		

Links

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

Formula

Empirical: a(n) = 27*a(n-1) -243*a(n-2) +729*a(n-3) for n>4.

Empirical: g.f. 3*x-x^2*(245-1538*x+3213*x^2) / (9*x-1)^3. - R. J. Mathar, Sep 29 2013