A229588 Number of defective 3-colorings of a 3 X n 0..2 array connected horizontally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order.

0, 40, 264, 1620, 9156, 49848, 264300, 1374048, 7036116, 35600376, 178380156, 886616784, 4377006372, 21483378600, 104919416268, 510169843584, 2471194910580, 11929478452824, 57413851328028, 275566856985648

Offset

1,2

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 29*a(n-2) + 20*a(n-3) - 4*a(n-4) for n>6.

Empirical g.f.: 4*x^2*(10 - 34*x + 35*x^2 - 47*x^3 + 37*x^4) / (1 - 5*x + 2*x^2)^2. - Colin Barker, Sep 19 2018

Example

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

Crossrefs

Row 3 of A229586.

Sequence in context: A290127 A115170 A247406 * A334121 A117216 A035099

Adjacent sequences: A229585 A229586 A229587 * A229589 A229590 A229591

Keyword

nonn

Author

R. H. Hardin, Sep 26 2013

Status

approved