A229633 Number of defective 3-colorings of an n X 4 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.

3, 122, 1109, 10227, 89331, 747299, 6049298, 47723226, 368769958, 2801445986, 20980532622, 155235487082, 1136689596246, 8248224017298, 59378458285438, 424468785559258, 3015393888558342, 21301249097825858, 149716107860461294

Offset: 1

Author

R. H. Hardin, Sep 27 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 4 of A229637.

Formula

Empirical: a(n) = 21*a(n-1) - 159*a(n-2) + 511*a(n-3) - 636*a(n-4) + 336*a(n-5) - 64*a(n-6) for n>9.

Empirical g.f.: x*(3 + 59*x - 976*x^2 + 4803*x^3 - 9539*x^4 + 7326*x^5 - 1825*x^6 - 76*x^7 + 25*x^8) / (1 - 7*x + 4*x^2)^3. - Colin Barker, Sep 20 2018