A229632 Number of defective 3-colorings of an nX3 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order

1, 40, 244, 1496, 8800, 50084, 277996, 1513104, 8106632, 42869740, 224232436, 1161920760, 5972173872, 30479422388, 154582269500, 779632820512, 3912450838808, 19545592617532, 97246103407556, 482032538140680

Offset

1,2

Comments

Column 3 of A229637

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -81*a(n-2) +185*a(n-3) -162*a(n-4) +60*a(n-5) -8*a(n-6) for n>7.

Empirical: g.f. x -4*x^2*(2*x-5)*(12*x^4-45*x^3+47*x^2-17*x+2) / (2*x^2-5*x+1)^3. - R. J. Mathar, Sep 29 2013

Example

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

Crossrefs

Sequence in context: A068790 A073962 A267391 * A223426 A290127 A115170

Adjacent sequences: A229629 A229630 A229631 * A229633 A229634 A229635

Keyword

nonn

Author

R. H. Hardin, Sep 27 2013

Status

approved