A229582 Number of defective 3-colorings of an n X 4 0..2 array connected horizontally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order.

6, 116, 1620, 19764, 224532, 2440692, 25745364, 265720500, 2697594516, 27033340788, 268094978388, 2636009007156, 25732468879380, 249667710249204, 2409688805255892, 23151313964420532, 221538858133842324

Offset: 1

Author

R. H. Hardin, Sep 26 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 4 of A229586.

Formula

Empirical: a(n) = 18*a(n-1) - 81*a(n-2) for n>3.

Conjectures from Colin Barker, Sep 19 2018: (Start)

G.f.: 2*x*(3 + 4*x + 9*x^2) / (1 - 9*x)^2.

a(n) = 4 * 9^(n - 2) * (16*n - 3) for n>1.

(End)